22-28 July 2018
Kellogg Hotel and Conference Center
EST timezone
Home > Contribution List

Contribution List

Displaying 326 contributions out of 326
Type: Poster Session: Poster reception
We report our preliminary results for the $B \to D^{(*)}\ell\nu$ semileptonic form factors at zero and nonzero recoils in 2+1 flavor QCD. The Moebius domain-wall action is employed for light, charm and bottom quarks at lattice cutoffs $a^{-1}$ = 2.5 and 3.6 GeV. We take bottom quark masses up to 2.4 times the physical charm mass to control discretization effects. We test the heavy quark scali ... More
Presented by Dr. Takashi KANEKO on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We discuss a calculation of the form factors for the flavor-changing charged current $b\to u$ and the flavor-changing neutral current $b\to d$ semileptonic decays, $B\to \pi\ell\nu$ and $B\to\pi\ell\ell$. HISQ light and NRQCD $b$ valence quarks are simulated on the MILC $N_f=2+1$ asqtad ensembles, including pion momenta that cover the full kinematic range of the decay. These data are analyzed us ... More
Presented by Christopher BOUCHARD on 27 Jul 2018 at 4:50 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present preliminary blinded results from our analysis of the form factors for B¯→D⋆ℓν¯ decay at non-zero recoil. Our analysis includes 15 MILC asqtad ensembles with Nf=2+1 flavors of sea quarks and lattice spacings ranging from a≈0.15 fm down to 0.045 fm. The valence light quarks employ the asqtad action, whereas The b and c quarks are treated using the Fermilab action. We discuss th ... More
Presented by Dr. Alejandro VAQUERO on 27 Jul 2018 at 2:20 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present progress on an ongoing calculation of the $B_s\to D_s l\nu$ form factors calculated on the 2+1+1 MILC ensembles and using the Highly Improved Staggered Quark action for all valence quarks. We perform the calculation at unphysically light $b$ quark masses and extrapolate to the physical point.
Presented by Mr. Euan MCLEAN on 27 Jul 2018 at 2:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
I will discuss a recent lattice QCD investigation of $DK$ scattering relevant for near-threshold charm-strange mesons such as the enigmatic $D_{s0}(2317)$. By employing a range of techniques, we extracted finite-volume spectra in a number of different channels. These were used to map out the energy dependence of the scattering amplitudes. The resonance and bound state content was determined by stu ... More
Presented by Mr. Gavin CHEUNG on 26 Jul 2018 at 9:50 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Two pentaquarks $P_{c}^{+}$ were discovered by LHCb collaboration as peaks in the $J/\psi$-nucleon invariant mass. We performed the lattice QCD study of the scattering between $J/\psi$ meson and nucleon in the channels with $J^{P}=\frac{3}{2}^{+},\frac{3}{2}^{-}, \frac{5}{2}^{+}, \frac{5}{2}^{-}$, where $P_{c}^{+}$ was discovered. Energies of the eigenstates in these channels are extracted for th ... More
Presented by Ms. Ursa SKERBIS on 27 Jul 2018 at 3:40 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In this project, we aim to compute the form factors relevant for $B \to K^*(\to K \pi)\ell^+\ell^-$ decays. To map the finite-volume matrix elements computed on the lattice to the infinite-volume $B \to K \pi$ matrix elements, the $K \pi$ scattering amplitude needs to be determined using L\"uscher's method. Here we present preliminary results from a calculation with $2+1$ flavors of dynamical clov ... More
Presented by Mr. Jesus Gumaro RENDON SUZUKI on 26 Jul 2018 at 9:30 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Elastic $I=1/2$, $s$- and $p$-wave $K\pi$ scattering amplitudes are simultaneously calculated using a Lüscher style analysis on a single ensemble of dynamical Wilson-clover fermions at $m_\pi \sim 230$MeV. Partial wave mixing due the reduced rotational symmetries of the finite volume is included up to $\ell=2$. We also present finite-volume QCD spectra on two large anisotropic lattices ($3 ... More
Presented by Ruairí BRETT on 26 Jul 2018 at 8:50 AM
Session: Algorithms and Machines
Track: Algorithms and Machines
A traditional approach for constructing a gauge field theory on a lattice employs a basic Wilson type procedure with additional enhancements to this formulation in order to improve computational performance and accuracy. This type of lattice gauge formulation has been successfully implemented on many different high performance computing systems and has yielded useful computational results. With ... More
Presented by Dr. Patrick DREHER on 24 Jul 2018 at 4:50 PM
Session: Theoretical Developments
Track: Theoretical Developments
Tensor renormalization group is a new type of numerical method which does not suffer from the sign problem. We have developed the tensor renormalization group for 3-dimensional $Z_2$ gauge theory. We apply it to finite temperature $Z_2$ gauge thery in (2+1) dimensions and compare the results with those obtained by a previous Monte Carlo study.
Presented by Yusuke YOSHIMURA on 26 Jul 2018 at 9:50 AM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We report on advances in the non-perturbative determination of the ratio $Z_\mathrm{S}/Z_\mathrm{P}$ of the scalar to the pseudoscalar renormalization constants in three-flavour lattice QCD with Wilson-clover quarks and tree-level Symanzik improved gluons. The computations are based on the Ward identity approach, using Schrödinger functional boundary conditions. Our results for $Z_\mathrm{S}/ ... More
Presented by Mr. Fabian JOSWIG on 26 Jul 2018 at 9:50 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Supersymmetric gauge theories are a popular building block of theories beyond the standard model. We investigate the pure gauge sector of Super-QCD focusing on the bound states, i.e. mesonic gluinoballs, gluino-glueballs and pure glueballs. To improve chiral symmetry as well as supersymmetry at finite lattice spacing, we introduce a deformed Super-Yang-Mills lattice action. It contains a twist ter ... More
Presented by Mr. Marc STEINHAUSER on 27 Jul 2018 at 5:50 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
$\mathcal{N}=1$ Supersymmetric QCD (SQCD) is a possible building block of theories beyond the standard model. It describes the interaction between gluons and quarks with their superpartners, gluinos and squarks. Since supersymmetry is explicitly broken by the lattice regularization, a careful fine-tuning of operators is necessary to obtain a supersymmetric continuum limit. For the pure gauge sect ... More
Presented by Dr. Björn WELLEGEHAUSEN on 27 Jul 2018 at 5:30 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
The use of Heavy Quark Effective Theory (HQET) on the lattice as an approach to B-physics phenomenology is based on a non-perturbative matching of HQET to QCD in finite volume. As a first step to apply the underlying strategy in the three-flavor ($N_f = 2+1$) theory, we determine the renormalization constant and improvement coefficients relating the renormalized current and subtracted quark mass o ... More
Presented by Simon KUBERSKI on 26 Jul 2018 at 10:10 AM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
This year, 2018, the QUDA library for Lattice QCD on NVIDIA GPUs celebrates its tenth birthday. QUDA has evolved from an acceleration library for solvers into an open-source framework for developing QCD simulations. It supports many different fermion discretizations, and features algorithms like adaptive multigrid, deflation and block Krylov-space methods. QUDA uses various techniques such as mixe ... More
Presented by Dr. Saul COHEN on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We report recent progress in determining $\varepsilon_K$, the indirect CP violation parameter in the neutral kaon system, calculated using lattice QCD inputs including $B_K$, $\xi_0$, $\xi_2$, $V_{us}$, $V_{cb}$, and $m_c(m_c)$. In this report, various other input parameters such as $m_t(m_t)$ have also been updated recently.
Presented by Prof. Weonjong LEE on 27 Jul 2018 at 3:00 PM
Type: Parallel Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In the isobar parametrization the three-particle states are populated via an interacting two-particle system (resonant or non-resonant), and a spectator. Using this formulation, we derive the isobar-spectator amplitude such that the three-body Unitarity is ensured exactly (arXiv:1706.06118). Unitarity constrains the imaginary parts of such an amplitude, which determine the power-law finite-volu ... More
Presented by Dr. Maxim MAI on 23 Jul 2018 at 4:30 PM
Session: Theoretical Developments
Track: Theoretical Developments
In general, perturbative expansions of observables in quantum field theories are divergent (asymptotic) series. It is often possible to apply resummation techniques to assign a unique finite value to the asymptotic series, but a particular pattern of divergence, the so-called renormalon, gives rise to non-perturbative ambiguities. The framework of numerical stochastic perturbation theory (NSP ... More
Presented by Dr. Matthias PUHR on 26 Jul 2018 at 11:40 AM
Session: Theoretical Developments
Track: Theoretical Developments
A lattice version of the widely used Functional Renormalization Group (FRG) for the Legendre effective action is solved (exactly) in terms of a linked cluster expansion. The graph rules invoke only one-line irreducible and a new type of labeled tree graphs. Conversely, the FRG induces nonlinear flow equations governing suitable resummations of the graph expansion. The correspondence is ... More
Presented by Mr. Rudrajit BANERJEE on 27 Jul 2018 at 5:30 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
One of the most challenging tasks in lattice calculations of hadronic form factors is the analysis and control of excited-state contaminations. Taking the isovector form factors of the nucleon as an example, a simple calculation in chiral effective field theory shows that the excited-state contributions become dominant when the axial current is spatially distant from the nucleon source location. I ... More
Presented by Mr. Tobias SCHULZ on 25 Jul 2018 at 2:20 PM
Session: Theoretical Developments
Track: Theoretical Developments
In most lattice simulations, the variables of integration are compact and character expansion (for instance Fourier analysis for $U(1)$ models) can be used to rewrite the partition function and average observables as discrete sums of contracted tensors. This reformulations have been used for RG blocking but they are also suitable for quantum computing. We discuss FAQ about tensorial reformulatio ... More
Presented by Yannick MEURICE on 26 Jul 2018 at 9:10 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We present the first ab initio calculations of nuclei and nuclear matter at finite temperature. Using lattice Monte Carlo simulations and chiral effective field theory, we probe the thermal properties of nuclear systems from first principles. We find that the pinhole algorithm, initially developed for extracting nucleon densities, is well suited for computing the canonical partition function. We e ... More
Presented by Dr. Bingnan LU on 27 Jul 2018 at 3:00 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We publish an extension of openQCD-1.6 with AVX512 vector instructions using Intel intrinsics. Recent Intel processors support extended instruction sets with operations on 512-bit wide vectors, increasing both the capacity for simultaneous floating point operations and of register memory. Optimal use of the new capabilities requires a reorganisation of data and floating point operations into these ... More
Presented by Dr. Jarno RANTAHARJU on 25 Jul 2018 at 4:50 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present a systematic study of finite size correction and cut-off effect in hadronic vacuum polarization contribution to muon g-2 with two volumes, 5.4 fm$^3$ and 10.8 fm$^3$, and two lattice cut-off, 2.33 GeV and 3.06 GeV, at the physical pion on the PACS configuration. In this analysis, using high statistics data, we compare two volumes at long-distance on the physical point to directly estima ... More
Presented by Dr. Eigo SHINTANI on 24 Jul 2018 at 4:50 PM
Session: Hadron Structure
Track: Hadron Structure
The QCDSF collaboration has generated an ensemble of configurations with dynamical QCD and QED fields. They are generated with the specific aim of studying flavour breaking effects arising from differences in the quark masses and charges in physical quantities. Here we study these effects in a calculation of the anomalous magnetic moment of the muon $a_\mu=(g-2)/2$ around an SU(3) symmetric point. ... More
Presented by James ZANOTTI on 27 Jul 2018 at 3:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We investigate the axial $U(1)$ symmetry in the phase above the critical temperature in $N_f=2$ lattice QCD, where the ensembles are generated with Mobius domain-wall fermions, and the overlap/domain-wall reweighting is applied. We show the $U(1)_A$ susceptibility extracted from the spectra of the overlap Dirac eigenmodes and discuss its temperature, quark-mass, and spatial volume dependence. The ... More
Presented by Dr. Kei SUZUKI on 24 Jul 2018 at 2:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Using MILC ensembles of highly improved staggered quarks (HISQ) with lattice spacings down to a=.044 fm, we report results obtained from heavyonium and heavy-charm HISQ correlators. Using HISQ valence quarks on successively finer lattices allows us to simulate near (and in fact just beyond) the b-quark mass. In particular we focus on the Bc(2S) energy, which we compare with O($\alpha_s$)-improve ... More
Presented by Dr. Andrew LYTLE on 27 Jul 2018 at 2:20 PM
Session: Theoretical Developments
Track: Theoretical Developments
We explore new representations for lattice gauge theories with fermions, where the space time lattice is divided into dynamically fluctuating regions, inside which different types of degres of freedom are used in the path integral. The first kind of regions is a union of so-called bags, in which the dynamics is described by the free propagation of composite degrees of freedom of the original fermi ... More
Presented by Carlotta MARCHIS on 27 Jul 2018 at 3:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The determination of baryon interactions is of crucial importance to understand the origin of nuclei, the mechanism of supernovae and the gravitational waves emitted from the binary neutron star mergers. In this talk, we review the latest results for the first lattice QCD calculation of baryon interactions with (almost) physical quark masses (m_pi=146 MeV) obtained by the time-dependent HAL QCD me ... More
Presented by Takumi DOI on 27 Jul 2018 at 5:30 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We describe our recent lattice study of the baryon spectrum of SU(4) gauge theory with fully dynamical Wilson-clover fermions in the fundamental and sextet representations. This system is closely related to a model of physics beyond the Standard Model containing a composite Higgs. The model also contains a partially composite top quark, which mixes linearly with a new baryon of SU(4) containing fe ... More
Presented by Mr. William JAY on 26 Jul 2018 at 12:20 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
In $\mathcal{N} = 1$ supersymmetric Yang-Mills theory the superpartner of the gluon is the gluino, which is a spin 1/2 Majorana particle in the adjoint representation of the gauge group. Combining three gluinos, it is possible to form colour neutral bound states, analogous to baryons in QCD. The correlation functions of the corresponding baryonic operators contain a contribution represented by a " ... More
Presented by Mr. Sajid ALI on 27 Jul 2018 at 4:30 PM
Type: Parallel Session: Chiral Symmetry
Track: Chiral Symmetry
Motivated by lattice QCD calculations in external fields, we study the behavior of single- and few-baryon systems in large magnetic fields. The dependence of single-baryon energies on magnetic fields is explored using chiral dynamics. Lattice calculations are argued to provide a valuable diagnostic on the chiral expansion for baryons. In particular, we show the unsatisfactory state of predictions ... More
Presented by Mr. Amol DESHMUKH on 25 Jul 2018 at 4:50 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The charmonium-like hybrid mesons with $J^{PC}=(0,1,2)^{-+}$ and $1^--$ are investigated on anisotropic lattices in the quenched approximation. For these states, we construct spatially extended operators by splitting the $\bar{c}\Gamma c B$-type operators into two parts ($c\bar{c}$ and the chromo-magnetic field strength $B$) with different spatial distances $r$. In the Coulomb gauge, the matrix el ... More
Presented by Mr. Yunheng MA on 25 Jul 2018 at 5:10 PM
Session: Theoretical Developments
Track: Theoretical Developments
Finding positive representations of complex weights still attracts a fair amount of interest. Extension of probabilistic Langevin dynamics into a complex domain works in some cases and fails in the others. For that reason some attempts were made to directly construct pairs of corresponding distributions, without invoking stochastic processes. One of such schemes, and its new theoretical and prac ... More
Presented by Jacek WOSIEK on 27 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Fermionic field theories at finite density suffer from a sign problem, making lattice calculations exponentially expensive in the volume. This sign problem can be reduced or eliminated by complexifying configuration space, and integrating over a contour deformed from the real plane. We present an algorithm for determining integration contours with reduced sign problems. We give results from this a ... More
Presented by Scott LAWRENCE on 23 Jul 2018 at 4:30 PM
Type: Parallel Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present the results of our lattice QCD study of the $\pi\gamma\to\pi\pi$ process, where the $\rho$ resonance appears as an enhancement in the transition amplitude. We use Nf=2+1 clover fermions on a lattice of L=3.6 fm and a pion mass of 320 MeV. Using a combination of forward, stochastic and sequential propagators we calculate the two-point and three-point functions required in the determinat ... More
Presented by Dr. Luka LESKOVEC on 25 Jul 2018 at 3:20 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present our preliminary result of the form factor of $K \to \pi l \nu$ semileptonic decays on the large volume configuration, $L \approx 10$ fm, with the physical $m_{\pi}$ and $m_{K}$ using the stout-smearing clover quark and Iwasaki gauge actions at $a^{-1}=2.333$ GeV. From an interpolation using the data in small momentum transfers, we determine the semileptonic decay form factors at z ... More
Presented by Mr. Junpei KAKAZU on 25 Jul 2018 at 2:20 PM
Session: Hadron Structure
Track: Hadron Structure
Recently, it has been shown that a class of coordinate-space-separated non-local hadronic matrix elements, computable directly in lattice QCD, can be factorized into parton distribution functions with calculable coefficients, in the same manner as the hadronic cross sections measured in an experiment [Phys.Rev.Lett. 120 (2018) no.2, 022003]. The pion and kaon, the lightest pseudo scalar mesons, pr ... More
Presented by Raza SUFIAN on 24 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Exploring the phase diagram of QCD at finite density is a challenging problem since first-principle calculations based on standard Monte Carlo methods suffer from the sign problem. As a promising approach to this issue, the complex Langevin method (CLM) has been pursued intensively. In this talk, we investigate the applicability of the CLM in the vicinity of the deconfinement phase transition ... More
Presented by Dr. Shoichiro TSUTSUI on 23 Jul 2018 at 2:20 PM
Type: Plenary Session: Plenary
Track: Weak Decays and Matrix Elements
Plans are well underway in Japan and the US to measure neutrino mixing angles with unprecedented precision and search for CP-violating phases in the mixing. An important systematic/theory uncertainty will be that of the neutrino-nucleus cross section. In this talk I illustrate how lattice QCD calculations (combined with nuclear many-body theory and experimental data) can reduce the uncertainty o ... More
Presented by Dr. Andreas KRONFELD on 27 Jul 2018 at 11:45 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
I will present a status update of RBC/UKQCD's charm (to bottom) physics program based on ensembles with $N_f=2+1$ flavours of domain wall fermions featuring physical pion masses. After a brief review of our program, the main focus will be on mesonic decay constants and neutral meson mixing in the charm and bottom sector, where results for the bottom sector are obtained from an extrapolation fro ... More
Presented by Dr. J Tobias TSANG on 26 Jul 2018 at 9:30 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We calculate the spectrum of charmed baryons on $32^3\times64$, $2+1$-flavor lattice QCD ensembles generated by the PACS-CS Collaboration. Calculations are done with almost physical light quarks, $m_\pi$ ~ 156 MeV, and physical strange and charm quarks. A relativistic heavy-quark action is used for valance charm quarks to suppress the systematic errors. A two-fold variational analysis is employed ... More
Presented by Dr. Utku CAN on 27 Jul 2018 at 2:40 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In this talk we report on the lattice QCD calculations of the interactions between a charmonium (either $\eta_c$ and $J/\psi$) and a nucleon. We use the method introduced by the HAL QCD collaboration to compute potentials, which guarantees the interaction to be faithful to the QCD S-matrix below the open-charm threshold. Our lattice simulation is performed with $2+1$ flavor full QCD gauge configur ... More
Presented by Mr. Takuya SUGIURA on 27 Jul 2018 at 6:10 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The chiral phase transition temperature $T_{c}$ is a fundamental quantity of QCD. To determine this quantity, we have performed simulations of (2 + 1)-flavor QCD using the Highly Improved Staggered Quarks (HISQ) action on $N_{\tau}=6, 8, 12$ lattices and aspect ratios $N_{\sigma}/N_{\tau}$ ranging from 4 to 7. In our simulations, we fix the strange quark mass value to its physical value $m_{s}^{ ... More
Presented by Mr. Sheng-Tai LI on 26 Jul 2018 at 11:20 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We investigate the properties of the finite-temperature QCD transition towards the chiral limit using staggered quarks. Starting from the 2+1 flavor physical point, the limit of massless quarks is approached along two different trajectories in the Columbia-plot. Unlike in previous approaches, the chiral condensate is determined via the Banks-Casher relation. The first results of our fi ... More
Presented by Dr. Gergely ENDRODI on 26 Jul 2018 at 11:40 AM
Session: Algorithms and Machines
Track: Algorithms and Machines
We report on recent work to integrate and optimize QUDA's adaptive multi-grid solver into Chroma RHMC Wilson-clover gauge evolution. Particular emphasis has been paid to optimization for the new Volta-powered Summit supercomputer. When combined with other recent improvements into Chroma's molecular dynamics implementation, in moving from Titan to Summit we achieve close to an aggregate 100x impr ... More
Presented by Dr. Kate CLARK on 25 Jul 2018 at 4:10 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
The global all-to-all communications in the Krylov subspace iterative methods is one of the major performance-limiting factors on large-scale parallel machines. In this report we give a brief overview of recent algorithmic approaches to mitigate communication cost in the iterative solvers. We present several variants of communication-optimized fermion matrix inverters implemented in the QUDA ... More
Presented by Alexei STRELCHENKO on 23 Jul 2018 at 4:30 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We investigate the influence of dynamical charm quarks on observables with an explicit charm quark dependence, like the hyperfine splitting, quark masses and meson decay constants. For this purpose, instead of working in full QCD we study a simplified setup. We simulate two theories: $N_f=0$ QCD and QCD with $N_f=2$ degenerate charm quarks. The absence of light quarks allows us to reach extremel ... More
Presented by Mr. Salvatore CALI on 27 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We are applying complex-Langevin simulations to lattice QCD at finite quark-number chemical potential $\mu$ and zero temperature. While we observe some improvement as we move to weaker coupling we only find agreement with the expected physics at very small and at large $\mu$. It has been observed by others that at least part of the problem is that at small and even zero $\mu$ the gauge field ... More
Presented by Donald SINCLAIR on 23 Jul 2018 at 2:00 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Some recent beyond Standard Model phenomenology is based on new strongly interacting dynamics of SU(N) gauge fields coupled to various numbers of fermions. When N=3 these systems are analogues of QCD, although the fermion masses are typically different from the ones of real world QCD. Many quantities needed for phenomenology from these models have been computed on the lattice. We are writing ... More
Presented by Thomas DEGRAND on 26 Jul 2018 at 11:40 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We compute hybrid static potentials in SU(3) lattice gauge theory using a method to automatically generate a large set of suitable creation operators from elementary building blocks. This method allows us to find a set of creation operators, which generate trial states with large ground state overlap for several angular momentum and parity channels. We present results for the corresponding hybrid ... More
Presented by Mr. Christian REISINGER on 24 Jul 2018 at 2:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The jet transport coefficient $\hat{q}$ is the leading parameter that controls the modification of hard jets produced in heavy-ion collisions. This coefficient, like other jet coefficients is inherently non-perturbative, and hence, is challenging to compute from first principles. Currently, existing theoretical model to data comparisons require a separate normalization of $\hat{q}$ between RHIC an ... More
Presented by Mr. Amit KUMAR on 26 Jul 2018 at 10:10 AM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
Dual superconductor picture is a promising scenario for quark confinement. For quarks in the fundamental representation, we have presented a new formulation of Yang-Mills theory on the lattice, where decomposed restricted fields play the dominant role in confinement, and demonstrated numerical evidences for the dual superconductivity. To establish this picture, we must show evidences for vari ... More
Presented by Akihiro SHIBATA on 23 Jul 2018 at 4:50 PM
Type: Parallel Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In this talk, we will introduce the finite-volume effects in the chiral effective field theory and analyse the lattice finite-volume energy levels to extract the resonance properties with the unphysical and physical pion masses. Special attention will be paid to the a0(980) from the coupled-channel scattering of pi-eta, K-Kbar and pi-eta'. Preliminary results on the D-pi, Ds-Kbar and D-eta scatter ... More
Presented by Dr. Zhihui GUO on 24 Jul 2018 at 2:40 PM
Session: Hadron Spectroscopy and Interactions
Track: Theoretical Developments
We present the construction of constraint HMC algorithms for gauge-Higgs models in order to measure the effective Higgs potential. In particular we focus on a SU(2) Gauge-Higgs Unification model on a 5D orbifold. Previous simulations have identified a region in the Higgs phase of this model which has properties of a 4D Abelian Higgs model. We want to test this relationship by compar ... More
Presented by Dr. Roman HÖLLWIESER on 23 Jul 2018 at 5:10 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We report our updated study on the critical endpoint of the finite temperature phase transition in 4-flavor QCD with Wilson-Clover fermions. Using the kurtosis intersection method, we determined the critical endpoint on lattices with $N_t$ = 4, 6 and 8. Our continuum extrapolated result shows that the critical pion mass is clearly larger compared to one in 3-flavor, which suggests that the critica ... More
Presented by Dr. Hiroshi OHNO on 26 Jul 2018 at 12:20 PM
Type: Poster Session: Poster reception
We describe a computation of the contribution to the anomalous magnetic moment of the muon from the disconnected part of the hadronic vacuum polarization. We use the highly-improved staggered quark (HISQ) formulation for the current density with gauge configurations generated with four flavors of HISQ sea quarks. The computation is performed by stochastic estimation of the current density using t ... More
Presented by Mr. Shuhei YAMAMOTO on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
Early B physics experiments have left us with a number of puzzles in heavy flavour physics. New lattice calculations and greater understanding of QCD effects in the Standard Model will be needed to support greater experimental precision in the coming years. In particular, the B meson decay constant is involved in calculations of CKM matrix elements and useful to measurements of the branching ratio ... More
Presented by Sophie HOLLITT on 25 Jul 2018 at 3:20 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
As all lattice calculations are subject to a trade-off between excited-state contamination at short Euclidean times and an increased signal-to-noise ratio at large Euclidean times, the need for reduced or removed excited-state effects is paramount. Perhaps the most notable in lattice calculations is that of the axial charge of the nucleon, wherein calculations have historically differed from the w ... More
Presented by Mr. Colin EGERER on 25 Jul 2018 at 2:40 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We use our Nf=2+1+1 staggered lattice QCD configurations to compute the corrections to Dashen's theorem and the quark mass ratio m_u/m_d. We use quark masses around their physical values, and reach the continuum limit using 5 different lattice spacings. We use the QED_L formulation, and include the QED and u-d mass difference effects in the valence sector.
Presented by Dr. Balint TOTH on 27 Jul 2018 at 3:20 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Many exotic charmonium resonances have been identified recently in experiment, however their nature and properties are mostly unknown. Algorithmic and theoretical progress in lattice calculations has enabled reliable numerical investigation of the charmonium spectrum below the strong decay threshold, while the study of resonances remain an open challenge. The main difficulty to overcome is the pre ... More
Presented by Dr. Stefano PIEMONTE on 27 Jul 2018 at 3:20 PM
Type: Parallel Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Chiral symmetry is presumed to be a crucial component in the strong interaction and QCD, but its role in spectroscopy, especially for baryons, has not been fully explored. Compounding this, chiral fermions are uncommon in lattice calculations due to their expensive nature. We calculate $\eta\pi$, $K\pi$ and $N\pi$ states with $q\bar{q}$ and $qqq$ interpolation fields at $a=0.0114\,\textrm{fm}$ o ... More
Presented by Dr. Jacob Fallica FALLICA on 26 Jul 2018 at 12:20 PM
Type: Parallel Session: Theoretical Developments
Track: Theoretical Developments
The critical phenomena of strongly interacting matter are studied in the random fluctuation walk model at finite temperature. The phase transitions are considered in systems where the Critical Point (CP) is a distinct singular one existence of which is dictated by the dynamics of conformal symmetry breaking. The physical approach to the effective CP is predicted through the influence fluctu ... More
Presented by Prof. Gennady KOZLOV on 27 Jul 2018 at 6:10 PM
Session: Applications beyond QCD
Track: Applications Beyond QCD
We study the curvature-curvature correlator for quantum gravity in the case of degenerate Euclidean Dynamical Triangulations, drawing on recent insights to modify the procedure for calculating connected correlation functions to reduce finite size effects. We find asymptotically a positive norm state, and a decay consistent with a power law, but cannot yet resolve what this power is in the continuu ... More
Presented by Mr. Scott BASSLER on 23 Jul 2018 at 2:20 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We calculate $D \rightarrow Kl\nu, \pi l\nu$ vector form factors $f_+^{K/\pi}$ at zero-momentum transfer, using MILC's $N_f = 2+1+1$ HISQ ensembles at four lattice spacings, $a \approx 0.042, 0.06, 0.09, 0.12$ fm, and various HISQ quark masses down to the (degenerate) physical light quark mass. We use the kinematic constraint $f_+= f_0$ at $q^2 = 0$ to determine the vector form factor from our stu ... More
Presented by Dr. Ruizi LI on 26 Jul 2018 at 8:30 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Systems of fermions at finite density have complex Boltzmann weights which cause the integrand of the path integral to be highly oscillatory. As a result of these oscillations, standard integration methods require exponential precision in the spacetime volume to compute observables. However, deforming the path integration contour to a manifold which approximates a set of Lefschetz Thimbles tames ... More
Presented by Neill WARRINGTON on 23 Jul 2018 at 4:50 PM
Session: Hadron Structure
Track: Hadron Structure
We present recent progress in the determination of nucleon sigma terms by the BMW collaboration. In this talk the lattice setup and analysis methods are discussed.
Presented by Mr. Lukas VARNHORST on 25 Jul 2018 at 4:10 PM
Session: Hadron Structure
Track: Hadron Structure
We present recent progress in the determination of nucleon sigma terms by the BMW collaboration. In this talk physical results are presented.
Presented by Dr. Christian HOELBLING on 25 Jul 2018 at 4:30 PM
Type: Poster Session: Poster reception
Track: Standard Model Parameters and Renormalization
We calculate the step scaling function for twelve fundamental flavors nonperturbatively by determining the gradient flow coupling on gauge field configurations generated with dynamical stout smeared Möbius domain wall fermions and Symanzik gauge action. Using Zeuthen, Symanzik, and Wilson flow we measure the energy density with three different operators. Our updated analysis is now based on up t ... More
Presented by Prof. Anna HASENFRATZ on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present a method of examining the efficacy of different formulations of the z-expansion in semileptonic B decays. We examine three different parameterizations of the z-expansion, the BGL, BCL and a recent Padé expansion. Our method involves fitting these parameterizations to the large momentum transfer data ($q^2$ > $17 ~GeV^2$) and seeing how well these parameterizations predict the low momen ... More
Presented by Mr. Erik GUSTAFSON on 27 Jul 2018 at 5:50 PM
Session: Hadron Structure
Track: Hadron Structure
Within the large momentum effective theory framework, we present the first direct lattice-QCD calculation of the valence quark distribution in the pion. Our results are comparable quantitatively with the results extracted from experimental data as well as from Dyson-Schwinger equation. Future calculations at physical pion mass and larger momentum will be able to discern discrepancies in various e ... More
Presented by Dr. Jianhui ZHANG on 24 Jul 2018 at 4:10 PM
Session: Hadron Structure
Track: Hadron Structure
In lattice QCD calculations, many different observables are measured on a gauge field, and their statistical fluctuations are correlated. By exploiting the correlation, one observable can be reconstructed from other observables, without expensive direct calculation. This idea is applied to two nucleon matrix element calculations using machine learning technique. (1) The calculations of nucleon ... More
Presented by Dr. Boram YOON on 26 Jul 2018 at 8:30 AM
Type: Poster Session: Poster reception
Track: Hadron Spectroscopy and Interactions
Eigenvector Continuation is a new method designed to aid in the calculation of lattice observables in situations where conventional methods, like perturbation theory, fails. We present the details of this method, and results for simulations of the Coulomb interaction in $^{4}$He and $^{8}$Be, using both Auxiliary Field Monte Carlo and Eigenvector Continuation.
Presented by Mr. Dillon FRAME on 24 Jul 2018 at 6:45 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We utilize the gradient flow to define and calculate electric dipole moments (EDMs) induced by the strong QCD $\theta$-term. Since the EDM is highly sensitive to the CP-violating operator induced in the action, the Euclidean time dependence of the topological charge is utilized to improve the signal to noise. The results of the nucleon EDMs are calculated on PACS-CS gauge fields (available f ... More
Presented by Dr. Jack DRAGOS on 24 Jul 2018 at 2:00 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We present a modification of the hybrid Monte Carlo algorithm for tackling the critical slowing down of generating Markov chains of lattice gauge configurations towards the continuum limit. We propose a new method to exchange information between an ensemble of Markov Chains, and use it to construct an approximate inverse Hessian matrix of the action inspired from Quasi-Newton algorithms for ... More
Presented by Xiaoyong JIN on 23 Jul 2018 at 2:40 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We calculate the equation of state at high temperatures in 2+1 flavor QCD using the highly improved staggered quark (HISQ) action. We study the lattice spacing dependence of the pressure at high temperatures using lattices with temporal extent (N_\tau= 6,\ 8,\ 10) and (12) and perform continuum extrapolations. We also give a continuum estimate for the equation of state up to temperatures (T = 2) ... More
Presented by Dr. Johannes Heinrich WEBER on 26 Jul 2018 at 8:50 AM
Type: Parallel Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study energy gap (latent heat) between the hot and cold phases at the first order phase transition point of the SU(3) gauge theory. Performing simulations on lattices with various spatial volumes and lattice spacings, we calculate the energy gap by a method using the Yang-Mills gradient flow and compare it with that by the conventional derivative method.
Presented by Mr. Mizuki SHIROGANE on 26 Jul 2018 at 8:30 AM
Session: Hadron Structure
Track: Hadron Structure
The momentum smearing technique opens a new window on the lattice simulation with the large hadron momentum, while the good signals are still limited to the data with small source-sink separations. Thus whether the systematic uncertainties from the excited state contaminations can be under control with the those small separations, will be crucial for the hadron matrix element calculation in the mo ... More
Presented by Yibo YANG on 23 Jul 2018 at 3:00 PM
Session: Hadron Structure
Track: Hadron Structure
The Hadronic Vacuum Polarization (HVP) is a dominant contribution to the theoretical uncertainty of the muon anomalous magnetic moment. The uncertainty in lattice QCD calculations of the HVP are dominated by the long-distance contribution to the vector correlation function. With explicit studies of the exclusive channels of the HVP diagram, it is possible to reconstruct the long-distance behavior ... More
Presented by Dr. Aaron MEYER on 27 Jul 2018 at 2:20 PM
Type: Parallel Session: Chiral Symmetry
Track: Chiral Symmetry
By performing a simultaneous extrapolation of $g_A$ and $m_N$, determined from recent lattice QCD calculations using the MDWF on gradient flowed HISQ action. We explore the convergence of SU(2) HBChiPT using expressions for $g_A$ and $m_N$ derived to a relatively high order.
Presented by Mr. Karl SALLMEN on 25 Jul 2018 at 4:30 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Monte Carlo studies of QCD at finite density suffer from the notorious sign problem, which becomes easily uncontrollable as the chemical potential increases for a moderate lattice size. In this work, we attempt to approach the high density low temperature region by the complex Langevin method (CLM). Simulations are performed on an 8^3 x 16 lattice using four-flavor staggered fermions wit ... More
Presented by Dr. Yuta ITO on 23 Jul 2018 at 3:00 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We report new results on the beta-function of an important BSM gauge theory with ten massless fermion flavors in the fundamental representation of the SU(3) color gauge group. The existence of an infrared fixed point (IRFP) was reported in [PoS LATTICE2016 (2017) 228] at $g^2 \sim 7.0$ of the renormalized gauge coupling. We find a positive and rapidly increasing beta-function in the extended ... More
Presented by Prof. Daniel NOGRADI on 25 Jul 2018 at 3:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
I will show that naive and staggered fermions on simplicial lattices and their dual lattices in any dimension can be formulated about as simply as on hypercubic lattices.  Point, chiral and discrete symmetry properties are however more subtle. Despite the absence of an exact chiral symmetry, there is no additive mass renormalization. There is an interesting duality between vector and axial vect ... More
Presented by Dr. Alan HOROWITZ on 26 Jul 2018 at 11:00 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In this talk, I will discuss a class of observables that are experimentally inaccessible but can be accessed via lattice QCD, and how these will shed light into the nature of low-lying QCD resonances and bound states. In particular, I consider the finite-volume two-body matrix elements with one current insertion, and review the recently proposed formalism for relating these to infinite-volume amp ... More
Presented by Alessandro BARONI on 26 Jul 2018 at 10:10 AM
Session: Theoretical Developments
Track: Theoretical Developments
Starting with the 2D Abelian Higgs model with the quartic self-coupling taken infinitely large we study the finite-size scaling of the Polyakov loop. We find an exponential decay for large temporal extents which is dictated by the energy gap between the ground states of a system with the Polyakov loop inserted, and one without. We study this system using the tensor renormalization group, and we ... More
Presented by Judah UNMUTH-YOCKEY on 25 Jul 2018 at 3:20 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
Parton distribution functions (PDFs) are central to the study of the hadron scattering cross sections with(within) collinear factorization. Recently, the Large-momentum effective theory (LaMET) introduced the quasi-PDF, providing the possibility to explore the entire PDF instead of just the first few moments. Since then, a lot of studies have been done on the quark quasi-PDFs. Compared to the quar ... More
Presented by Zhouyou FAN on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present first preliminary results for masses and decay constants of charmed mesons using a valence Nf=2+1+1 fully-twisted tmQCD action combined with an Nf=2+1 non-perturbatively O(a)-improved Wilson sea sector. The impact of various techniques to reduce noise and improve spectroscopic resolution is presented, and the scaling of basic observables towards the continuum limit explored in a subset ... More
Presented by Mr. Javier UGARRIO on 26 Jul 2018 at 9:10 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
In the past few years several observables are indicating deviations from the SM amounting to a few sigmas. In view of the experimental developments on the horizon and bearing in mind recent advances in matrix elements calculations, in this talk I will discuss ways in which lattice methods may be used to improve precision in the predictions of the SM so that the experimental data can be used more ... More
Presented by Amarjit SONI on 27 Jul 2018 at 6:10 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Finite-density calculations in lattice field theory are typically plagued by sign problems. A promising way to ameliorate this issue is the so-called "holomorphic flow" equations that deform the manifold of integration for the path integral to manifolds in the complex space where the sign fluctuations are less dramatic. In this talk, We will discuss some novel features of applying the flow equat ... More
Presented by Dr. Henry LAMM on 23 Jul 2018 at 5:10 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
In this work we present our latest results about the K $\to$ $\pi$ matrix elements at large $N_c$, including the exploration of the mass dependence and the latest simulations with $N_f=4$ dynamical fermions.
Presented by Mr. Fernando ROMERO-LOPEZ on 26 Jul 2018 at 12:00 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
The analysis of the Hybrid Monte Carlo (HMC) algorithm developed by Luscher and Schaefer is generalized to include Fourier acceleration. We show for the $\phi^4$ theory examined by Luscher and Schaefer that Fourier acceleration removes the non-renormalizable, singular behavior which they discovered and likely defines a renormalizable theory for the five-dimensional correlation functions in Euclid ... More
Presented by Prof. Norman CHRIST on 23 Jul 2018 at 2:00 PM
Type: Plenary Session: Plenary
The Facility for Rare Isotope Beams (FRIB) is a DOE national user facility being built at Michigan State University that will be a world leader in rare nuclear isotopes. The first part of the talk is an overview of the design and current status of the facility. The second part discusses the impact of FRIB on nuclear science, astrophysics, fundamental symmetries, and societal applications. The la ... More
Presented by Prof. Dean LEE on 23 Jul 2018 at 9:20 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Proper treatment of redundant gauge degrees of freedom seems necessary for gauge theories with terms that explicitly break gauge symmetry (e.g., in chiral gauge theories with manifestly local formulation of lattice fermions) since these degrees of freedom become manifestly present in such theories. There is also a no-go theorem prohibiting use of BRST formalism in theories with compact gauge field ... More
Presented by Prof. Asit Kumar DE on 24 Jul 2018 at 3:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
Quantum computers have the potential to solve certain problems in lattice gauge theory that are thought to be exponentially hard for classical computers. The proposed starting point for such computations has been the Kogut-Susskind Hamiltonian supplemented by the Gauss law constraint, with a cutoff on electric field values. There are several disadvantages to this approach, including having to simu ... More
Presented by Jesse STRYKER on 25 Jul 2018 at 3:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
Gaussian states, meaning states whose density matrix can be expressed as a Gaussian function in the creation and annihilation operators, are widely used in various areas to describe fermionic as well as bosonic systems. However, in cases where both bosons and fermions are present, they cannot describe any correlations between the two species beyond mean-field. This renders them at first glance uns ... More
Presented by Dr. Stefan KUEHN on 26 Jul 2018 at 8:50 AM
Type: Parallel Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present a first calculation of the first moments of gluon GPDs for a vector rho meson as it becomes unstable. We construct three-point functions in the forward limit using ‘optimized’ operators that interpolate a single state as well as a gluonic operator insertion. The two-point correlation functions have been constructed using the ‘distillation’ method. The correlators are calculated ... More
Presented by Dimitra PEFKOU on 23 Jul 2018 at 4:10 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
After introducing the fundamental difficulties of the two-baryon systems in lattice QCD, we review the severe problems in the previous studies by the direct method and reliabilities of the HAL QCD method. From the HAL QCD method, we study Nucleon-Omega interaction at almost physical quark masses. A strong attractive potential without a repulsive core is found in $^5$S$_2$ channel, and we discus ... More
Presented by Dr. Takumi IRITANI on 27 Jul 2018 at 5:10 PM
Session: Hadron Structure
Track: Hadron Structure
We present preliminary results for the (connected) hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment (g-2). The HVP is computed for degenerate up and down quarks at the physical point on HISQ 2+1+1 flavor ensembles generated by the MILC collaboration. We use all mode and low mode averaging with 2000-3000 lowmodes to obtain precise statistics. Calculations perfor ... More
Presented by Thomas BLUM on 27 Jul 2018 at 4:30 PM
Session: Hadron Structure
Track: Hadron Structure
We present a preliminary lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the light quarks to the anomalous magnetic moment of the muon including leading-order strong and electromagnetic isospin-breaking corrections. Our lattice results are obtained in an electro-quenched setup using the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) w ... More
Presented by Mr. Davide GIUSTI on 27 Jul 2018 at 5:10 PM
Type: Plenary Session: Plenary
Track: Hadron Spectroscopy and Interactions
​I review recent results on hadron spectroscopy using lattice QCD. In light of the recent discoveries in heavy baryon sector at LHCb, lattice calculations in this regard will be emphasized. Recent lattice calculations on light baryon, heavy-heavy and heavy-light meson resonances will also be discussed.
Presented by Dr. Padmanath MADANAGOPALAN on 25 Jul 2018 at 11:00 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In this talk we present our recent results of the elastic scattering length in the $I_3=\frac{3}{2}$ channel $\pi-K$ scattering. We show a new method to remove thermal effects in the interaction energy of the $\pi-K$ system, and present a careful continuum and chiral extrapolation of the scattering length.
Presented by Dr. Ferenc PITTLER on 26 Jul 2018 at 9:10 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Although the general behaviour of the crossover of QCD into the quark-gluon plasma phase at zero chemical potential is fairly well understood, the question of what exactly happens to the bound states of the theory in the crossover region is still not fully answered. In this talk the continuation of the FASTSUM collaboration's investigation of hadrons in the region of $T_c$ will be presented. The s ... More
Presented by Dr. Jonas GLESAAEN on 27 Jul 2018 at 5:10 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We report on the progress of our calculation of form factors for the exclusive semileptonic decay of B mesons to pions on $2+1$ flavour lattices with spacings from $0.080~\mathrm{fm}$ down to $0.044~\mathrm{fm}$. Using the Mobius domain wall fermion action for all quarks, we simulate pions with masses down 230 MeV over a range of momenta, and extrapolate to the bottom quark mass by utilising multi ... More
Presented by Dr. Brian COLQUHOUN on 26 Jul 2018 at 10:10 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We introduce a mixed-action approach based on CLS ensembles, where a valence Nf=2+1+1 fully-twisted tmQCD action is combined with the Nf=2+1 non-perturbatively O(a)-improved Wilson sea sector. Some field-theoretical properties of this setup (unitarity, O(a) improvement, relevance of open boundary conditions) are discussed. Particular emphasis is given to the application of this setup to heavy-quar ... More
Presented by Dr. Andrea BUSSONE on 26 Jul 2018 at 8:50 AM
Type: Poster Session: Poster reception
Track: Vacuum Structure and Confinement
We report on results for the Landau gauge gluon propagator computed from large statistical ensembles and look at the compatibility of the results with the Gribov-Zwanziger tree level prediction for its refined and very refined versions. Our results show that the data is well described by the tree level estimate only up to momenta p ≲1 GeV, while clearly favoring the so-called Refined Gribov-Zwan ... More
Presented by Dr. Paulo SILVA on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
Higher moments of patron distribution functions (PDFs) have evaded lattice QCD calculations due to the well-known problem of power-divergent mixing with low-dimension operators towards the continuum limit. With a new proposal for smeared and angular-momentum projected operators presented in Phys. Rev. D 86, 054505 (2012), we obtain moments of several PDFs of the pion, including the high moments pr ... More
Presented by Zohreh DAVOUDI on 25 Jul 2018 at 2:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
When comparing lattice calculation to experimental data from heavy ion collision experiments, the higher order fluctuations of conserved charges are important observables. An efficient way to study these fluctuations is to derive them from simulations at a set of imaginary chemical potentials. In this talk we present results for higher order derivatives with respect to $\mu_B$, $\mu_S$ and $\mu_Q$ ... More
Presented by Jana N. GUENTHER on 25 Jul 2018 at 4:30 PM
Type: Plenary Session: Plenary
Track: Weak Decays and Matrix Elements
Heavy flavor physics has entered a new era when the Belle II experiment observed its first collision. There are several hints found so far by BaBar, Belle, and LHCb in particular, that suggest the physics beyond the Standard Model appearing in the loop processes at short distances. They will be further tested by higher precision experiments in the coming years. The role of lattice QCD is ... More
Presented by Dr. Shoji HASHIMOTO on 24 Jul 2018 at 11:15 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present a preliminary study toward a lattice determination of the vector and scalar form factors of the $B \to \pi \ell \nu$ semileptonic decays. We compute the form factors relative to the transition between pseudo-scalar heavy mesons, with masses above the D-mass, and the pion. We simulate the valence heavy quark with a mass in the range $ m_c < m_h < 2m_c $. Lorentz symmetry breaking ... More
Presented by Dr. Lorenzo RIGGIO on 27 Jul 2018 at 4:30 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
The hyperon axial couplings are important parameters entering the low-energy effective field theory description of the octet baryons. In addition, the coupling constants appear in the non-leptonic decays of hyperons, and hyperon-hyperon and hyperon-nucleon scattering processes, which can be used in the description of neutron stars. In this poster, we present preliminary results on the Si ... More
Presented by Mr. Aditya SAVANUR on 24 Jul 2018 at 6:45 PM
Type: Poster Session: Poster reception
We port the most critical part of the Lattice Quantum Chromodynamics code, the iterative solver, to modern FPGA devices. More precisely, we discuss a single-node, double precision implementation of the Conjugate Gradient algorithm and use it to invert numerically the Dirac-Wilson operator on a 4-dimensional grid on a Xilinx Zynq evaluation board. We propose a separation of software/hardware pa ... More
Presented by Dr. Piotr KORCYL on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
The Feynman-Hellmann method, as implemented by Bouchard et al. [1612.06963], has recently been used successfully to determine the nucleon axial charge. A limitation of the method was the restriction to a single operator and a single momentum during the computation of each "Feynman-Hellmann" propagator. Here we discuss enhancements to the method that relax this constraint and we demonstrate the s ... More
Presented by Dr. Arjun GAMBHIR on 26 Jul 2018 at 11:00 AM
Type: Poster Session: Poster reception
Track: Weak Decays and Matrix Elements
A lattice calculation of inclusive decay structure functions for $B¥to X_c¥ell¥nu$ is compared with the corresponding estimates based on the heavy quark expansion. Both methods are applicable in the region away from the resonances/cuts due to final charmed states, and one can test the theoretical methods employed on both sides.
Presented by Dr. Shoji HASHIMOTO on 24 Jul 2018 at 6:45 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We present the results of a numerical investigation of SU(2) gauge theory with $N_f = 3/2$ flavours of fermions, corresponding to 3 Majorana fermions, which transform in the adjoint representation of the gauge group. At two values of the gauge coupling, the masses of bound states are considered as a function of the PCAC quark mass. The scaling of bound states masses indicates an infrared conformal ... More
Presented by Dr. Philipp SCIOR on 24 Jul 2018 at 2:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
Quantum field theories with a complex action suffer from a sign problem in stochastic non-perturbative treatments, making many systems of great interest - such as polarized or mass-imbalanced fermions and QCD at finite baryon density - extremely challenging to treat numerically. Another such system is that of bosons at finite angular momentum; experimentalists have successfully achieved vortex for ... More
Presented by Ms. Casey BERGER on 27 Jul 2018 at 3:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Using complex Langevin method we examine the phase structure of complex unitary matrix models and compare the numerical results with analytic results found at large number of colors. The actions we consider are manifestly complex, and thus the dominant contributions to the path integral comes from the space of complexified gauge field configurations. For this reason, the eigenvalues of unitary mat ... More
Presented by Dr. Anosh JOSEPH on 23 Jul 2018 at 3:20 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
We present a study of volume effects for Nf=2 twisted mass fermions using simulations at the physical point. The main focus will be given to nucleon quantities such as the axial charge and quark momentum fraction. The two volumes that we compare are 4.5fm and 6 fm
Presented by Colin LAUER on 24 Jul 2018 at 6:45 PM
Session: Theoretical Developments
Track: Theoretical Developments
We present results from our study of the 1+1 dimensional Thirring model employing the techniques of Matrix Product States. As the first step of a research programme for examining this model with the Hamiltonian formalism on the lattice, we determine the phase structure of the theory. In particular, we confirm the existence of the critical phase in the Thirring model in two dimensions. This is ... More
Presented by Prof. C.-J. David LIN on 26 Jul 2018 at 8:30 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We summarise the current status of our numerical simulations of N = 1 supersymmetric Yang-Mills theory with gauge group SU(3). We use the formulation of Curci and Veneziano with clover-improved Wilson fermions. The masses of various bound states have been obtained at different values of the gluino mass and gauge coupling. Extrapolations to the limit of vanishing gluino mass indicate that the ... More
Presented by Mr. Henning GERBER on 27 Jul 2018 at 4:50 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
There is a long running controversy over which SU(3) gauge theories with Nf massless fermion flavors in the fundamental representation are conformal, with particular focus on Nf = 12 and 10. In our studies of both theories, we have found no evidence of conformality as shown by an infrared fixed point of the beta function, in direct contradiction to claims by other groups covering the same range of ... More
Presented by Dr. Kieran HOLLAND on 25 Jul 2018 at 2:40 PM
Session: Hadron Structure
Track: Hadron Structure
A determination of the HVP contribution to g-2 from lattice QCD aiming at a precision of 1% requires to include isospin breaking corrections in the computation. We present a lattice calculation of the QED and strong isospin breaking corrections to the HVP with Domain Wall fermions. The results are obtained using quark masses which are tuned such that pion and kaon masses agree with their physical ... More
Presented by Dr. Vera GUELPERS on 27 Jul 2018 at 2:40 PM
Session: Hadron Structure
Track: Hadron Structure
I will present results from the PNDME collaboration for the isovector and flavor diagonal charges of the nucleon obtained using eleven 2+1+1-flavor HISQ ensembles generated by the MILC collaboration. The talk will also cover Details of the control over excited states and the the chiral-continuum-finite volume fits leading to teh final results.
Presented by Dr. Rajan GUPTA on 26 Jul 2018 at 12:40 PM
Session: Hadron Structure
Track: Hadron Structure
We present the first lattice-QCD calculation of the kaon distribution amplitude using the large-momentum effective theory (LaMET) approach. The momentum-smearing technique has been implemented to improve signals at large meson momenta. We subtract the power divergence due to Wilson line to high precision using multiple lattice spacings. The kaon structure clearly shows an asymmetry of the distribu ... More
Presented by Mr. Rui ZHANG on 24 Jul 2018 at 2:40 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
The RBC and UKQCD Collaborations have generated a number of coarse ensembles with 2+1 flavors of Mobius Domain Wall Fermions (MDWF) and physical quark masses using the Iwasaki plus Dislocation Suppressing Determinant Ratio (DSDR) action. Previous work has shown small $O(a^2)$ scaling violations for pseudoscalar decay constants, various masses and Wilson flow scales. In this talk, we presen ... More
Presented by Prof. Robert MAWHINNEY on 26 Jul 2018 at 11:00 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
I present an update on the calculation of beyond the standard model kaon mixing matrix elements in isospin symmetric pure QCD with $n_f$ = 2 + 1 dynamical flavours calculated with data at the physical pion mass. Our analysis includes simulations with domain wall fermions and an Iwasaki gauge, at three-lattice spacings and a range of pion masses from the physical point up to 430 MeV. We perform a ... More
Presented by Ms. Julia KETTLE on 27 Jul 2018 at 3:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
To date, studies of the thermodynamics of QCD in the limit of large number of colors have been limited to the quenched approximation, i.e., the behavior of pure SU(N) gauge theory at large N. We present a progress report on our investigation of the phase structure of large-N QCD in the presence of (Wilson) fermions with finite mass. We explore the light quark mass regime by simulating with two fla ... More
Presented by Daniel HACKETT on 26 Jul 2018 at 12:40 PM
Session: Hadron Structure
Track: Hadron Structure
We present a lattice-QCD calculation of the isovector parton distribution function (PDF) within the framework of large-momentum effective theory (LaMET). We detail the systematics that affect PDF calculations, providing guidelines to improve the precision of future lattice PDF calculations. We find our final parton distribution to be in reasonable agreement with the PDF provided by the latest phen ... More
Presented by Dr. Yu-Sheng LIU on 23 Jul 2018 at 3:20 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
The charge radius of the proton has been measured in scattering and spectroscopy experiments using both electronic and muonic probes. The electronic and muonic measurements have a currently unresolved five sigma discrepancy, giving rise to what is known as the proton radius puzzle. Since the neutron charge radius is known, measurement of the proton charge radius on the lattice typically involve ... More
Presented by Anthony GREBE on 24 Jul 2018 at 6:45 PM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
We discuss the subtleties concerning the lattice computation of the ghost propagator in linear covariant gauges, and present preliminary numerical results.
Presented by Dr. Paulo SILVA on 23 Jul 2018 at 4:10 PM
Session: Theoretical Developments
Track: Theoretical Developments
We explain our recent formulation of this theory on the lattice, and also discuss other formulations. Issues related to tuning and decoupling of auxiliary sectors are examined. The continuum limit is explored.
Presented by Prof. Joel GIEDT on 26 Jul 2018 at 12:20 PM
Type: Plenary Session: Plenary
Low-energy tests of fundamental symmetries are extremely sensitive probes of physics beyond the Standard Model (SM), reaching scales that are comparable, if not higher, than directly accessible at the energy frontier. The interpretation of low-energy precision experiments and their connection with models of BSM physics relies on controlling the theoretical uncertainties induced by the non-perturba ... More
Presented by Emanuele MEREGHETTI on 23 Jul 2018 at 10:00 AM
Session: Hadron Structure
Track: Hadron Structure
We report preliminary results on the lattice calculation of the hadronic tensor of the nucleon. Two topologically distinct connected-insertions of the Euclidean 4-point function are considered which helps to separate the connected-sea parton contribution from that of the valence. Converting the Euclidean hadronic tensor to that in the Minkowski space, which involves an inverse problem in a Laplace ... More
Presented by Jian LIANG on 23 Jul 2018 at 4:50 PM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
We are developing a code package for the supercomputer Shenwei Taihu-Light in China. There is an optimized D-slash function and some inverter functions in the code pacakge. We will show the working progress of this project.
Presented by Ming GONG on 24 Jul 2018 at 6:45 PM
Type: Plenary Session: Plenary
Track: Algorithms and Machines
In the 10 years since the creation of the QUDA library for Lattice QCD on NVIDIA GPUs the hardware and software features of GPU systems have evolved dramatically. Not only has the raw Dslash kernel performance on a single GPU improved by more than one order of magnitude but also modern GPUs are often deployed in "Fat Nodes" with up to 8 GPUs. We report on the techniques that QUDA implements to ach ... More
Presented by Dr. Mathias WAGNER on 28 Jul 2018 at 9:45 AM
Type: Poster Session: Poster reception
We present our experiences porting Lattice QCD code to upcoming ARM processor architectures, which will be used for future supercomputers such as QPACE 4 (University of Regensburg, Germany) and Post-K (RIKEN, Japan). These processors will support the ARM Scalable Vector Extension (SVE). SVE allows to design processor cores providing significantly higher performance compared to the cores avail ... More
Presented by Dr. Nils MEYER on 24 Jul 2018 at 6:45 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The observed abundance of matter over anti-matter in the universe suggests the need for beyond the Standard Model sources of CP-violation. This has motivated a significant experimental effort to search for among other things, permanent electric dipole moments (EDMs) in nucleons, light and also extremely heavy nuclei. The interpretation of nuclear EDMs is clouded by large theoretical uncertaintie ... More
Presented by Andre WALKER-LOUD on 25 Jul 2018 at 4:10 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
We report our calculation of the neutron electric dipole moment of the contribution from the $\theta$ term with overlap fermions on the 2+1-flavor RBC/UKQCD domain wall lattices 24I and 32ID. For the 24I lattice the size is 2.65 fm and the pion mass is 337 MeV and for the 32ID lattice the size is 4.58 fm and the pion mass is 171 MeV. In order to solve the large-volume problem, the cluster-decompos ... More
Presented by Jian LIANG on 24 Jul 2018 at 6:45 PM
Session: Applications beyond QCD
Track: Applications Beyond QCD
We consider the lattice gravity model based on Euclidean dynamical triangulations incorporating degenerate tiling with a non-trivial measure term and couple it minimally to a scalar field in the quenched approximation. Our preliminary results suggest a multiplicative renormalization for the mass of the scalar field which is consistent with the shift symmetry of the discretized lattice action. We d ... More
Presented by Mr. Raghav Govind JHA on 23 Jul 2018 at 2:40 PM
Type: Plenary Session: Plenary
The dominating uncertainty in the Standard Model prediction of the muon g-2 is coming from the hadronic contributions. The Muon g-2 experiment at Fermilab has started the major data collection and the aimed four-fold increase in precision will shed light on the current discrepancy between the theory prediction and the measured value. A reciprocal effort to directly measure the hadronic contributio ... More
Presented by Prof. Krstic Marinkovic MARINA on 25 Jul 2018 at 9:30 AM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We present a preliminary analysis of the $u/d$ and $s$ quark masses, extracted using the PCAC quark masses reported in Phys. Rev. D 95, 074504. The data is based on the CLS $N_f = 2 + 1$ simulations with Wilson/Clover quarks and Luescher-Weisz gauge action, at four $\beta$ values (i.e. lattice spacings) and a range of quark masses. We use the Alpha results of Eur.Phys.J. C78 (2018)387 for non-pert ... More
Presented by Dr. Jonna KOPONEN on 27 Jul 2018 at 2:20 PM
Session: Hadron Structure
Track: Hadron Structure
Using the approach proposed a few years ago by X. Ji, it has become feasible to extract parton distribution functions (PDFs) from lattice QCD, a task thought to be practically impossible before Ji's proposal. In this talk, we discuss the recent progress in this approach concerning renormalization and matching and we set the stage for the following talk where results by the ETM Collaboration are pr ... More
Presented by Dr. Krzysztof CICHY on 23 Jul 2018 at 2:00 PM
Type: Poster Session: Poster reception
Track: Weak Decays and Matrix Elements
Recently four experiments have demonstrated new levels of sensitivity to neutrinoless double beta ($0\nu\beta\beta$) decay. Such decay, if exists, would prove that neutrinos are Majorana fermions. The light-neutrino exchange is the most popular mechanism to explain the $0\nu\beta\beta$ decay. In this mechanism, the decay amplitude is proportional to the effective neutrino mass $m_{\beta\beta}$ and ... More
Presented by Prof. Xu FENG on 24 Jul 2018 at 6:45 PM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
We study the spatial distribution of the stress tensor around static quark-anti-quark pair in SU(3) lattice gauge theory. In particular, we reveal the transverse structure of the stress tensor distribution in detail by taking the continuum limit. The Yang-Mills gradient flow plays a crucial role to make the stress tensor well-defined and derivable from the numerical simulations on the lattice [1] ... More
Presented by Mr. Ryosuke YANAGIHARA on 23 Jul 2018 at 5:10 PM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
At high temperature part of the spectrum of the quark Dirac operator is known to consist of localized states. This comes about because around the cross-over temperature to the quark-gluon plasma, localized states start to appear at the low end of the spectrum and as the system is further heated, states higher up in the spectrum also get localized. Since localization and the crossover to the c ... More
Presented by Prof. Tamas G. KOVACS on 24 Jul 2018 at 4:50 PM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
It is known that at high temperature the lowest eigenmodes of the QCD Dirac operator become localized. Since these localized modes appear around the cross-over temperature it is natural to ask how they are related to deconfinement and chiral symmetry restoration. The simplest question one can ask in this connection is whether deconfinement and the appearance of localization happen at the sam ... More
Presented by Ms. Réka Ágnes VIG on 24 Jul 2018 at 4:30 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study a complex $\phi^4$ field at finite temperature and finite density using a worldline representation. In particular we focus on the low temperature regime where the particle number shows condensation steps as a function of the chemical potential. The critical values of the chemical potential, i.e., the condensation thresholds, are related to the mass and higher multi-particle energies and c ... More
Presented by Oliver ORASCH on 24 Jul 2018 at 4:50 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
Critical slowing-down of HMC algorithms presents a significant challenge in achieving LQCD calculations at fine lattice spacings. A number of methods have been proposed that circumvent this issue by acting at multiple physical length scales, including perfect actions that aim to achieve almost-continuum physics at finite lattice spacings, and multi-scale thermalisation techniques. Such approaches ... More
Presented by Prof. Phiala SHANAHAN on 24 Jul 2018 at 4:30 PM
Session: Theoretical Developments
Track: Theoretical Developments
We illustrate how principal component analysis of simulation data represented as images generated from the worm algorithm, a method to sample the strong coupling contributions, can be used to identify the critical temperature Tc in the Ising model. It is shown that the eigenvalue corresponding to the first principal component of the covariance matrix obtained from pixel ensembles scales logarithmi ... More
Presented by Mr. Samuel FOREMAN on 27 Jul 2018 at 3:40 PM
Type: Plenary Session: Plenary
Track: Algorithms and Machines
I will review recent progress in software development for lattice QCD on novel architectures and new machines. I will also report some algorithmic advancements in ensemble generation, solvers and contractions.
Presented by Dr. Meifeng LIN on 28 Jul 2018 at 9:00 AM
Type: Poster Session: Poster reception
Track: Physics Beyond the Standard Model
We examine mass splittings in a linear sigma model which is an effective theory for a SU(3) gauge theory with $N_1$ flavors of mass $m_1$ and $N_2$ flavors of mass $m_2$. We discuss the consequences for current simulations done by various collaborations. We explain the relevance for BSM model building.
Presented by Mr. Erik GUSTAFSON on 24 Jul 2018 at 6:45 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We present a preliminary lattice determination of the masses and decay constants of the pseudoscalar and vector mesons $B_c$ and $B_c^*$. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with $N_f=2+1+1$ flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. Heavy-quar ... More
Presented by Dr. Giorgio SALERNO on 26 Jul 2018 at 9:50 AM
Type: Poster Session: Poster reception
Track: Weak Decays and Matrix Elements
We will present a detailed description of the matching of a valence Nf=2+1+1 fully-twisted tmQCD action with an Nf=2+1, non-perturbatively O(a)-improved Wilson sea. Extensive preliminary results for meson and quark masses, as well as for pseudoscalar decay constants, are available for several CLS ensembles. A comparison of the scaling behaviour of the two actions in the light and strange quar ... More
Presented by Mr. Jose Angel ROMERO JURADO on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
The quasi parton distribution (quasi-PDF) is an equal-time correlation of quarks along the direction the nucleon is moving at. At large but finite nucleon momentum, the quasi parton distribution can be perturbatively matched to the PDF through a factorization formula in large momentum effective theory. Following a nonperturbative renormalization of the quasi parton distribution in a regularization ... More
Presented by Dr. Yong ZHAO on 23 Jul 2018 at 2:40 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
In the lattice gauge theory with Wilson fermion, chiral symmetry is explicitly broken. A non-trivial additive correction is needed to renormalize the chiral condensate. In this study, we use gradient flow to avoid this problem. Gradient flow makes us possible to define correctly renormalized chiral susceptibility without additive renormalization. We measure not only disconnected diagram but also ... More
Presented by Mr. Atsushi BABA on 26 Jul 2018 at 12:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We report on the progress of understanding spatial correlation functions in high temperature QCD. We study isovector meson operators in Nf=2 QCD using domain-wall fermions on lattices of Ns=32 and different quark masses. It has previously been found that at $\sim 2 T_c$ these observables are not only chirally symmetric but in addition approximately $SU(2)_{CS}$ and $SU(4)$ symmetric. In this ... More
Presented by Mr. Christian ROHRHOFER on 27 Jul 2018 at 5:50 PM
Type: Poster Session: Poster reception
Track: Hadron Structure
Lattice QCD can provide direct determination of the electromagnetic form factors of mesons as a prediction to be compared to upcoming experiments at Jefferson Lab. At the same time we can compare to expectations from perturbative QCD, which take a very simple form at high Q^2. We will show recent results from HPQCD, building on the work in 1701.04250. We give predictions for pi and K mesons up ... More
Presented by Prof. Christine DAVIES on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
We will show our calculation of the moments of pion distribution amplitude using a method proposed in Phys.Rev.D73:014501(2006) [hep-lat/0507007]. Since the method requires a fine lattice, it becomes practical only recently. The procedure is based on calculating the suitable, bilocal current-current products sandwiched between a pion state and vacuum on the lattice. Then the lattice calculations o ... More
Presented by Dr. Santanu MONDAL on 24 Jul 2018 at 3:00 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
With the ever-growing number of computing architectures, performance portability is an important aspect of (Lattice QCD) software. The Grid library provides a good framework for writing such code, as it thoroughly separates hardware-specific code from algorithmic functionality and already supports many modern architectures. The Regensburg group (RQCD) decided to deprecate its Xeon Phi version of ... More
Presented by Mr. Daniel RICHTMANN on 23 Jul 2018 at 4:50 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
The computation of hadronic correlation functions in lattice QCD is severely hindered by a signal-to-noise ratio that exponentially decreases with the distance between source and sink. Recent developments for the factorization of both the fermion propagator and the fermion determinant pave the way for the implementation of multilevel Monte Carlo integration techniques, which are already known to ... More
Presented by Dr. Alessandro NADA on 23 Jul 2018 at 3:00 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We combine multi-level integration with a variance-reduction technique for the stochastic estimate of disconnected diagrams of various bilinear operators, and present preliminary numerical results with O($a$)-improved Wilson fermions.
Presented by Dr. Tim HARRIS on 23 Jul 2018 at 3:20 PM
Session: Hadron Structure
Track: Hadron Structure
Using a combination of lattice QCD calculation of the strange-quark form factors, and experimental (anti) neutrino differential cross-section data in a regime where nuclear effects are shown to be negligible, we obtain a precise determination of the weak axial form factor in the regime $0\le Q^2 \le 1\, {\rm GeV}^2$, and of the corresponding weak-axial charge. We are thereby able to reproduce the ... More
Presented by Dr. David RICHARDS on 26 Jul 2018 at 12:20 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Fundamental symmetry tests of baryon number violation in low-energy experiments can test beyond the Standard Model explanations of the matter-antimatter asymmetry of the universe. Neutron-antineutron oscillations are predicted to be a signature of many baryogenesis mechanisms involving low-scale baryon number violation. This work presents the first complete lattice quantum chromodynamics calcula ... More
Presented by Dr. Enrico RINALDI on 23 Jul 2018 at 2:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present a new lattice formulation of chiral effective nuclear force with simpler decomposition into partial waves. With these new interactions the process of fitting to the empirical-observed scattering phase shifts is simplified, and the resulting lattice phase shifts are more accurate than those in precious studies. We present results for neutron-proton system up to next-to-next-to-ne ... More
Presented by Dr. Ning LI on 24 Jul 2018 at 3:00 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
New results are discussed on the effective field theory of the light 0++ scalar in an important near-conformal strongly coupled BSM gauge theory and its lattice simulations in the sextet fermion representation. Relevant for the composite BSM Higgs, two distinct scenarios are introduced for the emergent light scalar as the composite σ-particle of chiral symmetry breaking or the dilaton of conforma ... More
Presented by Julius KUTI on 25 Jul 2018 at 2:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
Numerical Stochastic Perturbation Theory (NSPT) enables very high order computations in Lattice Gauge Theories. We report on the determination of the gluon condensate from lattice QCD measurements of the basic plaquette. This is a long standing problem, which was eventually solved a few years ago in pure gauge. In this context NSPT is crucial: it is actually the only tool enabling the subtraction ... More
Presented by Prof. Francesco DI RENZO on 26 Jul 2018 at 12:00 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
In this talk we present a numerical lattice study of a SU(3) gauge model where a SU(2) doublet of non-Abelian strongly interacting fermions is coupled to a complex scalar field doublet via a Yukawa and a Wilson-like term. Despite the presence of these two chiral breaking operators in the Lagrangian, the model enjoys an exact symmetry, acting on all fields, which prevents UV power divergent fermion ... More
Presented by Dr. Marco GAROFALO on 23 Jul 2018 at 3:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
We discuss a continuous real space renormalization group transformation based on gradient flow, allowing for a numerical study of renormalization without the need for costly ensemble matching. Applying the technique in a pilot study of SU$(3)$ gauge theory with $N_f = 12$ fermions in the fundamental representation, we find the mass anomalous dimension to be $\gamma_m = 0.23(6)$, consistent with o ... More
Presented by Prof. Anna HASENFRATZ on 27 Jul 2018 at 4:50 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode --- neutrinoless double beta decay ($0 \nu \beta \beta$) --- is a particularly interesting target of experimental searches, since its observation would imply both the violation of lepton number conservation in natu ... More
Presented by Dr. David MURPHY on 24 Jul 2018 at 3:00 PM
Session: Hadron Structure
Track: Hadron Structure
Searches for the nucleon electric dipole moments (EDMs) are at the frontier of high-precision Nuclear physics. Their discovery would be evidence of CP-violation, which is necessary to explain the origin of nuclear matter and would be a signature of new non-Standard-Model interactions. CP-violation in the quark-gluon sector can be caused by the presence of the QCD $\theta$-term or higher-order effe ... More
Presented by Prof. Sergey SYRITSYN on 26 Jul 2018 at 8:50 AM
Type: Parallel Session: Hadron Structure
Track: Hadron Structure
Nucleon form factors are not only interesting for understand the structure of the fundamental building blocks of nature, but they are also important input for various experiments such as neutrino facility. They are also related to the electric and axial radius of proton or nucleon, experimental results of which present some puzzles. We report form factor results on 2+1 DWQCD at physical point. ... More
Presented by Taku IZUBUCHI on 27 Jul 2018 at 5:30 PM
Session: Hadron Structure
Track: Hadron Structure
A precise determination of the nucleon axial form factor will greatly reduce systematic errors for the upcoming neutrino scattering experiments. There are no foreseeable experiments to perform such measurement so lattice QCD is the best tool to accomplish the task. Such calculations are especially timely, because the uncertainty on the axial form factor is often underestimated in experimental anal ... More
Presented by Mr. Yin LIN on 26 Jul 2018 at 9:10 AM
Session: Hadron Structure
Track: Hadron Structure
Better model-independent theoretical predictions and input to parton distribution functions are vital to improving our understanding of how the nucleon is formed by quarks and gluons. By using a second order extension of the Feynman-Hellmann theorem we examine the nucleon Compton form factor $F_1(\omega,Q^2)$ without the need for calculations of four-point correlators. The calculation is performed ... More
Presented by Mr. Kim SOMFLETH on 23 Jul 2018 at 5:10 PM
Session: Hadron Structure
Track: Hadron Structure
We present a nucleon structure analysis including the charges of isovector dimension-three operators as well as the forward matrix elements of twist-2, dimension-four operators. Computations are performed on CLS ensembles with $N_f=2+1$ Wilson fermions, covering four values of the lattice spacing and pion masses down to $M_\pi \approx 200\,\mathrm{MeV}$. Several source-sink separations (typically ... More
Presented by Dr. Konstantin OTTNAD on 26 Jul 2018 at 12:00 PM
Session: Hadron Structure
Track: Hadron Structure
The electromagnetic (EM) form factors of the nucleon are fundamental quantities probing its structure. They have been precisely determined from electron scattering experiments as well as extensively studied in lattice QCD calculations. Experiments seeking to explore the behavior of the EM form factors at high momentum transfer, such as the physics program of the CEBAF at JLab which will allow meas ... More
Presented by Dr. Christos KALLIDONIS on 26 Jul 2018 at 10:10 AM
Session: Hadron Structure
Track: Hadron Structure
We present results on the nucleon form factors including disconnected contributions using an ensemble of Nf=2+1+1 twisted mass fermions with a clover term. The ensemble has a spatial extent of 5.12fm (64^3 x128). Techniques such as the summation and the two-state fits have been employed to control possible excited states contamination.
Presented by Prof. Martha CONSTANTINOU on 27 Jul 2018 at 5:50 PM
Session: Hadron Structure
Track: Hadron Structure
We present preliminary results for nucleon form factors calculated with the plateau method varying the source-sink separation time t_s on a (10.8fm)^4 lattice at the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a)-improved Wilson quark action and the Iwasaki gauge action at beta=1.82 corresponding to the lattice spacing of 0.084 fm. We discuss the mom ... More
Presented by Prof. Yoshinobu KURAMASHI on 26 Jul 2018 at 9:50 AM
Session: Hadron Structure
Track: Hadron Structure
The current status of the nucleon isovector axialvector charge calculation using a 2+1-flavor dynamical domain-wall QCD ensemble generated jointly by RBC and UKQCD Collaborations with essentially physical mass quarks and at lattice cut off of 1.730(4) GeV will be reported.
Presented by Shigemi OHTA on 26 Jul 2018 at 11:40 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The nucleon-pion-state ($N\pi$) contribution to QCD two- and three-point functions used in the calculation of the axial form factors of the nucleon are studied in chiral perturbation theory. For physical quark masses the $N\pi$ states are expected to dominate the excited-state contamination at large euclidean time separations. To leading order in chiral perturbation theory the results depend on tw ... More
Presented by Dr. Oliver BAER on 25 Jul 2018 at 2:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Finite-volume (FV) effects are expected to be large in the presence of QED, due to the long range of the electromagnetic interaction. With large efforts under way to include QED effects in lattice calculations, it is important to understand and correct for the associated FV effects. We calculate universal QED FV effects numerically, using an efficient method for lattice simulation of scalar QED. W ... More
Presented by Mr. James HARRISON on 25 Jul 2018 at 4:30 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We perform an analysis of QCD lattice data on charmed meson masses. The quark-mass dependence of the data set is used to gain information on the size of counter terms of the chiral Lagrangian formulated with open-charm states with $J^P = 0^-$ and $J^P = 1^-$ quantum numbers. Of particular interest are those counter terms that are active in the exotic flavour sextet channel. A chiral expansion sche ... More
Presented by Dr. Xiao-Yu GUO on 27 Jul 2018 at 3:00 PM
Session: Hadron Structure
Track: Hadron Structure
Hadronic spectral functions of tau decays have been used in the past to provide an alternative determination of the LO Hadronic Vacuum Polarization relevant for (g-2) of the muon. Following recent developments and results in Lattice QCD+QED calculations, we explore the possibility of studying the isospin breaking corrections of tau spectral functions for this prediction. We present preliminary res ... More
Presented by Dr. Mattia BRUNO on 27 Jul 2018 at 3:00 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
In lattice simulations one generally projects correlators over zero spatial momentum to calculate masses and related spectral data. The sum over space lattice points, however, discards information which may be useful especially in the calculation of disconnected diagrams. I will show that, by using momentum conservation, the calculation of non-zero momentum components of disconnected diagrams an ... More
Presented by Claudio REBBI on 26 Jul 2018 at 11:00 AM
Type: Poster Session: Poster reception
Track: Standard Model Parameters and Renormalization
We propose a particular 'line of constant physics' (i.e., a scheme) for computing isospin breaking corrections to hadronic quantities. We show this scheme is in a class of schemes that allow for the separation of the electromagnetic and strong isospin breaking corrections at leading order, such that scheme-ambiguities are higher order in isospin breaking effects.
Presented by Dr. Andrea BUSSONE on 24 Jul 2018 at 6:45 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
I use the traditional and more recently discovered 1-form discrete 't Hooft anomaly matching conditions and propose a novel realization of the symmetries of SU(2) Yang-Mills theory with two massless adjoint Weyl fermions in the strongly-coupled regime. The theory has a spectrum identical to the one obtained by compactifying it on a small circle. This offers a new perspective on the lattice studies ... More
Presented by Dr. Mohamed ANBER on 25 Jul 2018 at 3:20 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We introduce an OpenCL library for computation of disconnected contributions for application with FPGAs and GPUs. We look at the advantages of FPGAs vs. traditional GPUs for stochastic estimation of disconnected contributions, as well as gains achieved with enhancements such as mixed precision and the truncated solver method. We also prospectively consider variance reduction algorithms and the adv ... More
Presented by Mr. Ahmed YOUSIF on 25 Jul 2018 at 4:30 PM
Session: Hadron Structure
Track: Hadron Structure
It has been recently proposed that PDFs can be studied directly using lattice QCD. Such studies require the evaluation of matrix of non-local operators. Since this was first proposed, there has been an intense investigation of all possible systematics except for the effects associated with the fact that lattice QCD is necessarily defined in a finite spacetime. In this talk, I present the first att ... More
Presented by Mr. Guerrero JUAN on 25 Jul 2018 at 2:00 PM
Type: Poster Session: Poster reception
We present a calculation of the low-lying spectra for the positive-parity Delta and Nucleon using the distillation approach applied on an isotropic $32^3 \times 64$ lattice at a pion mass of around 360 MeV, using a non-relativistic basis of operators together with so-called hybrid-type operators. The spectra are extracted from two-point functions using variational analysis. The results are compare ... More
Presented by Mr. Tanjib KHAN on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
We present numerical results on the bare quasi-PDF matric element for the pion. Our pion mass is $300$ MeV using a HISQ sea and Wilson-Clover valence quarks. Our lattice spacing and volume are $0.061$ fm an ... More
Presented by Charles SHUGERT on 24 Jul 2018 at 4:50 PM
Type: Plenary Session: Plenary
Track: Nonzero Temperature and Density
We introduce the feedforward neural network in the path optimization method (POM) to evade the sign problem in field theories. POM is based on the complexification of integral variables as in the complex Langevin method and the Lefschetz thimble method. The integration path is optimized in the complexified variable space by maximizing the average phase factor. In the last Lattice meeting [1] and i ... More
Presented by Prof. Akira OHNISHI on 28 Jul 2018 at 11:15 AM
Session: Poster reception
Track: Standard Model Parameters and Renormalization
We present matching factors for $Z_q$ calculated perturbatively at the one-loop level with improved staggered quarks. We calculate $Z_q$ with HYP-smeared staggered quarks and Symanzik-improved gluons in RI- and RI$'$-MOM scheme. Using the conversion factor, we also present $Z_q$ in MSbar scheme. As a byproduct, we present the quark mass renormalization facto ... More
Presented by Mr. Benjamin Jaedon CHOI on 24 Jul 2018 at 6:45 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Correlation functions for baryons, or generically systems with different U(1) charges than the vacuum, have phase fluctuations that lead to sign problems obstructing studies of finite-density matter using correlation functions. I will discuss phase fluctuations in lattice QCD and in a one-dimensional complex scalar field toy model and methods to exploit the structure of phase fluctuations to avoid ... More
Presented by Dr. Michael WAGMAN on 27 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Lattice QCD estimates of correlation functions with non-zero U(1) baryon number suffer from a well known signal-to-noise problem at large time separations. Previous work has shown that this can be attributed to a widening phase distribution over a circular domain, where standard estimators perform exponentially poorly as the distribution approaches uniform. We present a new approach to this proble ... More
Presented by Mr. Gurtej KANWAR on 27 Jul 2018 at 2:20 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Composite operators of bare fermion fields evolved along a trajectory on field space by means of flow equations get renormalised multiplicatively. Therefore, even in the case of Wilson fermions, the renormalization of expectation values of fermion operators can be simplified drastically on the lattice. We measure the gluino condensate in N=1 supersymmetric Yang-Mills theory at non-zero temperature ... More
Presented by Camilo LOPEZ on 27 Jul 2018 at 6:10 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
A SU(3) gauge theory with 12 flavors is a model of great interest for beyond the standard model physics. Running RHMC simulations for different masses and betas we study the Fisher zeroes in the vicinity of the endpoint of a line of first order transitions. The pinching of these zeros with respect to increasing volume provide information about a possible unconventional continuum limit. We also stu ... More
Presented by Mr. Diego SILVA on 26 Jul 2018 at 12:40 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We study a four dmensional lattice model comprising four reduced staggered fermions coupled to a scalar field through an SO(4) invariant interaction. Symmetries of the lattice theory prohibit fermion mass terms. If we switch of the kinetic term for the scalar field we obtain a model with a four fermion interaction which has been the focus of several recent lattice investigations. The results of ... More
Presented by Nouman BUTT on 24 Jul 2018 at 2:40 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study the phase structure of QCD with three degenerate flavors in external magnetic fields using HISQ fermions. The simulations are performed on $16^3\times6$ and $24^3\times6$ lattices. In order to investigate the quark mass dependence of the QCD transition we vary the values of quark masses from 0.015 to 0.0009375 corresponding to $m_\pi=320$ MeV and $80$ MeV in the continuum limit. We found ... More
Presented by Dr. Akio TOMIYA on 25 Jul 2018 at 5:10 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We investigate the lattice calculation of pi_0 transition form factor in coordinate space, which is relevant to hadronic light-by-light (HLbL) scattering in the muon g-2. I will describe how we construct the coordinate space formulation of the pion transition form factor. I will present preliminary results for the form factor computed on a physical pion mass, 24^3, 1.0 GeV, 2+1 flavor Mobius-DWF e ... More
Presented by Cheng TU on 24 Jul 2018 at 4:10 PM
Session: Hadron Structure
Track: Hadron Structure
We present the current status of a non-perturbative lattice calculation of the pion distribution amplitude by the RQCD collaboration. Our investigation is carried out using $N_f=2+1$ dynamical, non-perturbatively O(a)-improved Wilson fermions on the CLS ensembles with 5 different lattice spacings and pion masses down to the physical pion mass. A combined continuum and chiral extrapolation to the p ... More
Presented by Dr. Piotr KORCYL on 24 Jul 2018 at 3:20 PM
Session: Hadron Structure
Track: Hadron Structure
We present the form factor of pion using overlap fermion. We work on 2+1 flavor domain-wall configurations on $24^3\times 64$ lattice with lattice spacing $a=0.083 \, {\rm{fm}}$ and $32^3 \times 64$ lattice with lattice spacing $a=0.083 \, {\rm{fm}}$ genterated by RBC/UKQCD collaboration. With multi--mass algorithm, we do an extrapolatiion of finite lattice spacing and varies valence quark masses ... More
Presented by Gen WANG on 26 Jul 2018 at 11:20 AM
Session: Hadron Structure
Track: Hadron Structure
We study the feasibility to extract the leading twist pion distribution amplitude (DA) and the higher twist normalization constant from suitably chosen Euclidean correlation functions with two local currents at a spacelike separation. We demonstrate the advantages of considering several correlation functions simultaneously and extracting the pion DA from a global fit. This position space approach ... More
Presented by Dr. Philipp WEIN on 25 Jul 2018 at 2:40 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present preliminary results on the scattering of pseudoscalar, vector, and scalar mesons on a physical pion mass, 2+1 flavor mobius-DWF, ensemble with periodic boundary conditions (PBCs) generated by the RBC and UKQCD collaborations. Using all-to-all propagators, we produce thousands of correlator momentum combinations. Energy spectra and phase shifts, including excited states, are then e ... More
Presented by Daniel HOYING on 25 Jul 2018 at 3:00 PM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
We port Domain-Decomposed-alpha-AMG solver to K computer. The system has 8 cores and 16 GB memory par node, of which theoretical peak is 128 GFlops (82,944 nodes in total). Its feature, as many as 256 registers par core and as large as 0.5 byte/Flop ratio, requires a different tuning from other machines. In order to use more registers, we change some of the data structure and rewrite matrix ... More
Presented by Dr. Issaku KANAMORI on 24 Jul 2018 at 6:45 PM
Type: Plenary Session: Plenary
Track: Standard Model Parameters and Renormalization
We discuss the determination of quark masses using the MILC highly improved staggered-quark ensembles with four flavors of dynamical quarks. We extract quark masses from heavy-light pseudoscalar meson masses by making use of heavy quark effective theory (HQET) and continuum-QCD perturbative calculations. While heavy-light meson masses can be measured very precisely on lattice, perturbative calcula ... More
Presented by Dr. Javad KOMIJANI on 24 Jul 2018 at 10:45 AM
Type: Poster Session: Poster reception
Track: Nonzero Temperature and Density
We perform CLE simulations both in the confining and in the deconfining phases of QCD at large temperature and in a wide chemical potential domain (up to \mu/T ~10). We show preliminary results for the deconfining transition at \beta = 5.9 for 2 flavors of Wilson fermions. Most of the data are taken at rather large quark masses (m_\pi ~ 1GeV) and small spatial volumes (8^3 and 12^3 ). This and the ... More
Presented by Mr. Manuel SCHERZER on 24 Jul 2018 at 6:45 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
The light 0++ scalar can be probed for dilaton signatures in near-conformal gauge theories. A case study is presented for the analysis of the SU(3) gauge theory with two fermions in the two-index symmetric representation (sextet model). It is shown that statistical methods which are based on Bayesian Markov Chain Monte Carlo analysis are important for robust tests of dilaton fingerprints in latti ... More
Presented by Dr. Chik Him WONG on 25 Jul 2018 at 2:20 PM
Type: Plenary Session: Plenary
Track: Physics Beyond the Standard Model
Supersymmetry plays prominent roles in modern theoretical physics, as a tool to improve our understanding of quantum field theory, as an ingredient in many new physics models, and as a means to study quantum gravity via holographic duality. Lattice investigations of supersymmetric field theories have a long history but often struggle due to the interplay of supersymmetry with the discretization o ... More
Presented by David SCHAICH on 24 Jul 2018 at 9:00 AM
Type: Plenary Session: Plenary
Anchoring the nuclear interaction in QCD is a long-outstanding problem in nuclear physics. While the lattice community has made enormous progress in mesonic physics and single nucleon physics, continuum-limit physical-point multi-nucleon physics has remained out of reach. I will review CalLat's strategy for multi-nucleon spectroscopy and our latest results.
Presented by Dr. Evan BERKOWITZ on 23 Jul 2018 at 11:00 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We report on the status of our program to simulate Sp(2N) gauge theories on the lattice. Motivated by the potential realization of SU(4)/Sp(4) ~ SO(6)/SO(5) composite Higgs model, we first consider Sp(4) theories with two Dirac fermion flavors in the fundamental representation. Preliminary results of meson spectrum will be presented along with discussion of the lattice systematics. Toward partial ... More
Presented by Dr. JONG-WAN LEE on 24 Jul 2018 at 2:20 PM
Session: Hadron Structure
Track: Hadron Structure
In this presentation we will show theoretical developments that facilitate the better reconstruction of light cone parton distributions starting from reduced Ioffe time pseudo distributions calculated on the lattice. We also present our new results of parton distributions for the nucleon and pion from an $N_{\rm f}=2+1$ simulation of Wilson-clover fermions with stout smearing and tree-level tadpol ... More
Presented by Dr. Savvas ZAFEIROPOULOS, Joseph KARPIE on 23 Jul 2018 at 4:10 PM
Session: Hadron Structure
Track: Hadron Structure
In this presentation we will show theoretical developments that facilitate the better reconstruction of light cone parton distributions starting from reduced Ioffe time pseudo distributions calculated on the lattice. We also present our new results of parton distributions for the nucleon and pion from an $N_{\rm f}=2+1$ simulation of Wilson-clover fermions with stout smearing and tree-level tadpol ... More
Presented by Joseph KARPIE, Dr. Savvas ZAFEIROPOULOS on 23 Jul 2018 at 4:30 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
I present an update on work extending and applying the relativistic three-particle quantization conditions of Hansen/Sharpe, and Brice\~no/Hansen/Sharpe. This is based on work done in collaboration with Tyler Blanton, Ra\'ul Brice\~no, Max Hansen and Fernando Romero-Lopez. Topics include the numerical implementation of the quantization condition in the isotropic approximation, the generalization o ... More
Presented by Prof. Stephen SHARPE on 26 Jul 2018 at 11:00 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We investigate to which extent we can exploit the dependence of the order of the chiral transition on the number of light degenerate flavors $N_\text{f}$, re-interpreted as continuous parameter in the path integral formulation, as a means to perform a controlled chiral extrapolation and deduce the order of the transition for the case $N_\text{f}=2$, which is still under debate.
Presented by Dr. Francesca CUTERI on 26 Jul 2018 at 11:00 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
In this talk, we present our progress on the study of the electromagnetic corrections to $K\to\pi\pi$ decay. To provide an accurate Standard-Model determination of direct CP violation at the precision of O(10%), it is important to include the electromagnetic corrections, as such $O(\alpha_e)$ effects could be enhanced 22 times in principle due to the isospin mixing and the $\Delta I=1/2$ rule. On ... More
Presented by Prof. Xu FENG on 26 Jul 2018 at 12:20 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Significant experimental and theoretical efforts to determine the existence and nature of the $H$-dibaryon have been underway since its prediction in 1977. Yet, conclusive evidence for such a bound state is still lacking. Results from various lattice QCD calculations show substantial disagreement for the binding energy. Since there is no conclusive evidence for or against the existence of a bound ... More
Presented by Dr. Andrew HANLON on 26 Jul 2018 at 12:40 PM
Type: Poster Session: Poster reception
Track: Hadron Spectroscopy and Interactions
A Prony method is an algebraic approach to extracting spectral energies from hadronic correlation functions. The simplest example is the effective mass commonly used in lattice gauge theory. We show our exploration of this method to extract multiple excited states for a pion point-point correlation function for an SU(3) gauge theory with 8 flavors. We discuss our approach for dealing with close ... More
Presented by Ms. Kimmy CUSHMAN on 24 Jul 2018 at 6:45 PM
Session: Theoretical Developments
Track: Theoretical Developments
Conformal or near conformal QFTs would benefit from a rigorous non-perturbative lattice formulation beyond the flat Euclidean space, $\mathbb R^d.\;$ Although all UV complete QFT are known to be also perturbatively renormalizable on any smooth Riemann manifold, non-perturbative realization on simplicial lattices (triangulations) encounter difficulties as the UV cut-off isremo ... More
Presented by Prof. Richard C. BROWER on 26 Jul 2018 at 11:20 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Proton decay is one of possible signatures of baryon number violation, which has to exist to explain the baryon asymmetry and the existence of nuclear matter. Proton decays must be mediated through effective low-energy baryon number violating operators made of three quarks and a lepton. We calculate matrix elements of these operators between an initial proton and various final pseudoscalar mesons ... More
Presented by Jun-sik YOO on 23 Jul 2018 at 2:20 PM
Type: Plenary Session: Plenary
Track: Hadron Structure
We calculate the intrinsic quark and gluon spin contribution to the total proton spin using overlap fermions on Domain-wall ensembles. We find that the total quark spin, with the axial Ward identity satisfied, is ~40%, and the glue spin contribution is ~50% if the matching procedure in LaMET is neglected. The imperative non-perturbative renormalization to obtain the quark and glue angular momen ... More
Presented by Yibo YANG on 27 Jul 2018 at 10:00 AM
Presented by Prof. John PRESKILL on 28 Jul 2018 at 8:00 PM
Type: Plenary Session: Plenary
In the last few years, numerical simulations of QCD on the lattice have reached a new level of accuracy. A wide range of thermodynamic quantities is now available in the continuum limit and for physical quark masses. This allows a comparison with measurements from heavy ion collisions for the first time. I will review the state-of-the-art results from lattice simulations of QCD thermodynamics and ... More
Presented by Prof. Claudia Ratti RATTI on 23 Jul 2018 at 11:30 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We will present new state-of-the-art lattice QCD results on the chiral crossover temperature of QCD for moderately large baryon chemical potential. Firstly, we will present a more precise updated result for the QCD pseudo-critical temperature at zero baryon chemical potential, obtained from all possible second-order chiral susceptibilities that diverge in the chiral limit. Then we will present new ... More
Presented by Mr. Patrick STEINBRECHER on 25 Jul 2018 at 4:10 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The QCD phase diagram at finite temperature and density has a very rich physical structure which can be explored with first principle lattice QCD calculations. We study the QCD phase diagram of (2+1)-flavor QCD with imaginary chemical potential using HISQ action which has reduced taste breaking effects compared to the unimproved staggered quark action and hence may allow us to get close to the con ... More
Presented by Mr. Jishnu GOSWAMI on 25 Jul 2018 at 4:50 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
Predictions for pion and kaon leptonic decay constants in Lattice QCD have reached sub-percent level precision. Since it is expected that isospin breaking corrections become important at this level of precision, further progress on the lattice requires inclusion of these effects. Given the phenomenological relevance for instance in CKM analyses this seems a worthwhile endeavour. In this talk I pre ... More
Presented by Mr. James RICHINGS on 25 Jul 2018 at 3:00 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
A precise Standard Model prediction for the direct CP violation in the K -> \pi\pi decay process is of great importance in confronting experiments and constraining new physics. The state-of-art lattice QCD precision of this process will soon achieve a value for which QED effects can no longer be neglected. The inclusion of QED in such calculations is planned and the formalism to relate the finite- ... More
Presented by Mr. Yiming CAI on 26 Jul 2018 at 12:40 PM
Session: Theoretical Developments
Track: Theoretical Developments
Causal set theory, originally introduced by Rafael Sorkin, is a model of spacetime as a partially ordered set: an element of a set corresponds to a point in spacetime, while partial ordering corresponds to lightcone causal relation. There is no coordinate system: all of the geometry is to be deduced from partial ordering alone. Consequently, one has to rewrite Lagrangians in quantum field theory i ... More
Presented by Roman SVERDLOV on 26 Jul 2018 at 10:10 AM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
Lattice QCD provides several avenues for the high precision determination of quark masses. Using the RI-SMOM scheme applied to lattice calculations with the HISQ action, we obtain mass renormalisation factors that we use to provide strange and charm quark masses with 1% precision. The calculation involves the study of various sources of systematic uncertainty, including an analysis of possible non ... More
Presented by Mr. Daniel HATTON on 26 Jul 2018 at 8:30 AM
Session: Hadron Structure
Track: Hadron Structure
Quark orbital angular momentum (OAM) in the proton can be calculated directly given a Wigner function encoding the simultaneous distribution of quark transverse positions and momenta. This distribution can be accessed via proton matrix elements of a quark bilocal operator (the separation in which is Fourier conjugate to the quark momentum) featuring a momentum transfer (which is Fourier conj ... More
Presented by Michael ENGELHARDT on 25 Jul 2018 at 3:20 PM
Session: Hadron Structure
Track: Hadron Structure
Parton distribution functions (PDFs) provide a detailed description of hadron structure and are crucial inputs in analyses of collider data. PDFs have a non-perturbative nature and Lattice QCD provides an appropriate framework of their extraction. We present results on the iso-vector quasi-quark distribution functions using an ensemble of $N_f=2$ degenerate light quarks in the twisted mass f ... More
Presented by Ms. Aurora SCAPELLATO on 23 Jul 2018 at 2:20 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
The precision of lattice QCD computations of many quantities have reached such a precision that isospin breaking corrections, including electromagnetism, must be included if further progress is to be made in extracting fundamental information, such as the values of Cabibbo-Kobayashi-Maskawa matrix elements, from experimental measurements. I discuss the framework for including radiative corrections ... More
Presented by Prof. Chris SACHRAJDA on 25 Jul 2018 at 2:40 PM
Type: Plenary Session: Plenary
Track: Hadron Structure
First principles calculations of the Bjorken-x dependence of hadron structure have been a long-standing challenge for lattice QCD. This year marks a significant milestone: the first determinations of parton distribution functions, which capture the longitudinal momentum structure of fast-moving hadrons, at physical pion masses. Moreover, there has been significant progress in our understanding of ... More
Presented by Dr. Christopher MONAHAN on 27 Jul 2018 at 11:00 AM
Type: Plenary Session: Plenary
Track: Nonzero Temperature and Density
I will review the recent progress and results on the bulk thermodynamic properties of QCD matter from Lattice. In particular I will highlight the recent calculations of the equation of state, pressure of QCD matter to the finite baryon density regime as far as $\mu_B/T~2.5$, giving us some preliminary bounds on the location of the critical end-point. I will also stress upon the fact that ... More
Presented by Swagato MUKHERJEE on 24 Jul 2018 at 12:00 PM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
Numerical studies in lattice gauge theory require the organization and analysis of large volumes of data. These data and analyses thereof can be viewed as a sequence of maps and reductions, a structure that can be represented naturally using relational databases. Organized in this way, the analysis of even large, heterogenous datasets is straightforward to automate. We present in abstract our meth ... More
Presented by Daniel HACKETT on 24 Jul 2018 at 6:45 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We discuss an exact relation between the two-particle scattering amplitude and the Bethe-Salpeter (BS) wave function inside the interaction range in quantum field theory. In the relation the reduced BS wave function given by the BS wave function plays an essential role. Through the relation the on-shell and half off-shell amplitudes can be calculated. We also show that the solution of Schrodinger ... More
Presented by Takeshi YAMAZAKI on 26 Jul 2018 at 11:20 AM
Session: Theoretical Developments
Track: Theoretical Developments
Gradient flow has proved useful in the definition and measurement of renormalized quantities on the lattice. Recently, the fact that it suppresses high-modes of the field has been used to construct new, continuous RG transformations on the lattice, distinct from the usual blocking techniques in spin models and gauge theories. In this talk, we discuss two approaches to define an RG transformation w ... More
Presented by Andrea CAROSSO on 27 Jul 2018 at 5:10 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We use the Yang-Mills Gradient flow to study the NLO mixing of CP-violating operators in continuum QCD with special attention to Weinberg’s d=6 purely gluonic operator. This method allows for a clear derivation of the Wilson coefficients of the CP-violating effective action as they pertain to the renormalization group equation. This perturbative calculation is the first step towards a high-energ ... More
Presented by Mr. Matthew RIZIK on 26 Jul 2018 at 9:10 AM
Session: Applications beyond QCD
Track: Applications Beyond QCD
We study renormalization on the fuzzy sphere. We perform Monte Carlo simulation of a scalar field theory on the fuzzy sphere, which is described by a Hermitian matrix model. We show that correlation functions defined by using the Berezin symbol are made independent of the matrix size, which plays a role of a UV cutoff, by tuning a parameter of the theory. We also find that the theories on the phas ... More
Presented by Mr. Kohta HATAKEYAMA on 23 Jul 2018 at 3:20 PM
Session: Hadron Structure
Track: Hadron Structure
We present numerical results on the non-perturbative renormalization of the quasi-PDF operator as determined using Wilson-Clover valence fermions on HISQ ensembles at two different lattice spacings, with and without the explicit subtraction of the divergent Wilson line self-energy contribution. Then, we present some preliminary results on the renormalized pion quasi-PDF as well as the pion PDF as ... More
Presented by Dr. Nikhil KARTHIK on 24 Jul 2018 at 4:30 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
The two neutral kaon states in nature, the KL (long-lived) and KS (short-lived) mesons, are the two time-evolution eigenstates of the $K^0$ -- $\overline{K}^0$ mixing system. The prediction of their mass difference $\Delta M_K$ based on the Standard Model is an important goal of lattice QCD. In this talk, I will present preliminary results from a calculation of $\Delta M_K$ performed on an ensemb ... More
Presented by Mr. Bigeng WANG on 27 Jul 2018 at 3:40 PM
Type: Plenary Session: Plenary
Track: Hadron Structure
Recent lattice QCD results for hadron light-by-light scattering (HLbL) and its contribution to muon anomalous magnetic moments (g-2) will be reviewed. There are currently more than three standard deviations between the BNL experimental result and the theoretical prediction. The Fermilab/JPARC experiments will reduce the experimental uncertainty by a factor of four. The uncertainty of theory ... More
Presented by Dr. Luchang JIN on 25 Jul 2018 at 10:00 AM
Type: Plenary Session: Plenary
Track: Applications Beyond QCD
Composite Higgs Models explore the possibility that the Higgs boson is an excitation of a new strongly interacting sector giving rise to electro-weak symmetry breaking. After describing how this new sector can be embedded into the Standard Model of elementary particle physics meeting experimental constraints, I will review efforts by the community to explore the physics of this new strong interact ... More
Presented by Oliver Witzel WITZEL on 24 Jul 2018 at 9:30 AM
Type: Plenary Session: Plenary
Track: Hadron Structure
Recent lattice QCD results for hadron vacuum polarization (HVP) and its contribution to muon anomalous magnetic moments (g-2) will be reviewed. There currently exists tension of more than 3-sigma deviations in muon g-2 between the BNL experiment with 0.5 ppm precision and the Standard Model (SM) prediction with the QCD dispersion relation used for HVP. The lattice QCD predictions without recourse ... More
Presented by Dr. Kohtaroh MIURA on 25 Jul 2018 at 9:00 AM
Type: Poster Session: Poster reception
Track: Nonzero Temperature and Density
One of the main challenges in simulations on Lefschetz thimbles is the computation of the relative weights of contributing thimbles. In this paper we propose a solution to that problem by means of computing those weights using a reweighting procedure. Besides we present recipes for finding parametrizations of thimbles and anti-thimbles for a given theory. Moreover, we study some approaches to comb ... More
Presented by Mr. Felix ZIEGLER on 24 Jul 2018 at 6:45 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Variational method with valence overlap fermion is employed to calculate the Roper state on the $24^3 \times 64$ domain-wall fermion lattice at a = 0.114 and 330 MeV pion mass. It is found that the results are consistent with those from the sequential empirical Bayes (SEB) method. They are about 300 MeV lower than those with the clover fermion at comparable lattice spacing and pion mass. To unders ... More
Presented by Prof. Keh-Fei LIU on 26 Jul 2018 at 12:00 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
The Kaon bag parameter, $B_K$, is a key non-perturbative ingredient in the search for new physics through CP-violation. It parameterizes the QCD hadronic matrix element of the effective weak $\Delta S=2$ four quark operator which can only be computed non-pertubatively on the lattice. The perturbative matching of $B_K$ between the lattice renormalization schemes and $\overline{\mbox{MS}}$ scheme ha ... More
Presented by Ms. Sandra KVEDARAITE on 26 Jul 2018 at 8:50 AM
Session: Theoretical Developments
Track: Theoretical Developments
In this talk, we show that the gradient flow equation is defined in ${\small\cal N} = 1$ SYM in a way that is consistent with supersymmetry in the Wess-Zumino gauge. Using the perturbation theory, we find that two-point function of flowed gauge multiplet is UV-finite at the one-loop level when four dimensional SYM is renormalized.
Presented by Dr. Daisuke KADOH on 27 Jul 2018 at 5:50 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
I will discuss recent calculations of the matrix elements of scalar, axial and tensor quark bilinear operators in light nuclei at unphysically heavy values of the quark masses. Axial matrix elements control the Gamow-Teller decays of nuclei and have potential for precision tests of the Standard Model. Tensor matrix elements determine the quark chromo-electric dipole moment and are important in the ... More
Presented by Dr. William DETMOLD on 24 Jul 2018 at 2:40 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We perform scale setting for the MDWF on gradient flowed HISQ action. 18 different ensembles are used to perform an extrapolation of the omega baryon to the physical point. Various schemes of defining dimensionless variables to parameterize the light and strange quark mass are used to estimate systematic uncertainties in the scale setting.
Presented by Mr. Logan CARPENTER on 27 Jul 2018 at 3:00 PM
Session: Theoretical Developments
Track: Theoretical Developments
Scattering theory can be formulated given a representation of the quantum mechanical Hilbert space and a set of self-adjoint Poincar\'e generators satisfying cluster properties. These are both provided by the Osterwalder-Schrader reconstruction theorem, where the input is a collection of Euclidean-covariant reflection-positive distributions. In this representation both Hilbert space inner pr ... More
Presented by Prof. Wayne POLYZOU on 27 Jul 2018 at 2:40 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We evaluate scattering lengths by use of a scattering amplitude calculated with the Bethe-Salpeter wave function inside the interaction range. Scattering lengths of I=2 two pions are computed by both conventional and our methods with $m_\pi = 0.52-0.86$ GeV in the quenched lattice QCD. The results are compared with each other to confirm consistency. Furthermore, a half off-shell amplitude i ... More
Presented by Dr. Yusuke NAMEKAWA on 26 Jul 2018 at 11:40 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The two-scalar field model of Rummukainen and Gottleib is revisited, except the limit of large quartic couplings is not used and a Symanzik improved action is used. Isotropic lattices ranging from $16^3 \times 48$ to $53^3 \times 48$ are used, and the scattering phase shift is determined using a Lüscher analysis. Results from $K\pi$ and $N\pi$ scattering will also be presented.
Presented by Mr. Daniel DARVISH on 26 Jul 2018 at 8:30 AM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We report on our determination of form factors for Bs semi-leptonic decays and extract ratios to investigate lepton flavor universality violations. Our calculation is based on RBC-UKQCD's gauge field ensembles featuring 2+1 flavors of domain-wall fermions and Iwasaki gauge action at three lattice spacing of 1/a = 1.78, 2.38, and 2.77 GeV. In the valence sector we use domain-wall light, strange, an ... More
Presented by Oliver Witzel WITZEL on 27 Jul 2018 at 5:30 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We report the status of an ongoing lattice-QCD calculation of form factors for exclusive semileptonic decays of $B$~mesons with both charged currents ($B\to\pi\ell\nu$, $B_s\to K\ell\nu$) and neutral currents ($B\to\pi\ell^+\ell^-$, $B\to K\ell^+\ell^-$). The results are important for constraining or revealing physics beyond the Standard Model. This work uses MILC's (2+1+1)-flavor ensembles w ... More
Presented by Mr. Zechariah GELZER on 27 Jul 2018 at 5:10 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
A strong candidate to search for new physics Beyond the Standard Model is neutrinoless double beta decay. Observation of this very rare nuclear process which violates lepton number conservation, would imply the neutrino sector has a majorana mass component and may also provide an explanation for universe's matter-antimatter asymmetry. In the case a heavy majorana neutrino is exchanged in this proc ... More
Presented by Henry MONGE-CAMACHO on 24 Jul 2018 at 3:20 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We present recent developments on our lattice simulations of fully dynamical $SU(3)\times U(1)$. Including electromagnetic effects is critical for the next level of precision in phenomenology. Examples include calculating the (higher order) QED contributions to the hadronic-vacuum-polarization contribution to the muon anomalous magnetic moment and calculating the QED contributions to meson and bar ... More
Presented by Yuzhi LIU on 24 Jul 2018 at 4:10 PM
Session: Plenary
Presented by Prof. John PRESKILL on 28 Jul 2018 at 11:45 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Many scalar field theory models with complex actions are invariant under the antilinear ($\mathcal{PT}$) symmetry operation $L^{*}(-\chi)=L(\chi)$. Models in this class include $i \phi^3$, the Bose gas at finite density and Polyakov loop spin models at finite density. This symmetry may be used to obtain a dual representation where weights in the functional integral are real but not necessarily po ... More
Presented by Prof. Michael OGILVIE on 24 Jul 2018 at 4:10 PM
Type: Parallel Session: Algorithms and Machines
Track: Chiral Symmetry
We perform hybrid Monte-Carlo simulation of $N_f=2+1+1$ lattice QCD with domain-wall/overlap quarks at the physical point. The simulation is carried out on a $ 64^4 $ lattice with lattice spacing $a \sim 0.06$ fm, using the Nvidia DGX-1 (8 Volta GPUs interconnected by the NVLink). To attain the maximal chiral symmetry for a finite extent ($N_s =16$) in the fifth dimension, we use the optimal doma ... More
Presented by Prof. Ting-Wai CHIU on 25 Jul 2018 at 5:10 PM
Session: Theoretical Developments
Track: Theoretical Developments
Many research programs aiming to deal with the sign problem were proposed since the advent of lattice field theory. Several of these try to achieve this by exploiting properties of analytic functions. This is also the case for one of the approaches we're developing. There auxillary complex variables are introduced and desired weight is obtained after integrating them out. In this talk I will eluci ... More
Presented by Mr. Blazej RUBA on 27 Jul 2018 at 2:20 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
We show that using the multisplitting algorithm as a preconditioner for the conjugate gradient inversion of domain wall fermion Dirac operators effectively reduces the inter-node communication cost, at the expense of performing more on-node floating point operations. Compared to Schwarz domain decomposition solver algorithms our approach enforces Dirichlet boundary conditions consistently on the n ... More
Presented by Jiqun TU on 23 Jul 2018 at 4:10 PM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
We report on the chromoelectric and chromomagnetic fields generated by a static quark-antiquark pair at zero temperature in pure gauge SU(3). From the spatial structure of chromoelectric field we extract its nonperturbative part and discuss its properties.
Presented by Volodymyr CHELNOKOV on 23 Jul 2018 at 4:30 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The spectral function is the key for understanding the in-medium hadron properties as well as the transport properties of the medium. Such as the dissociation temperatures of quarkonia, diffusion coefficients, dilepton emission rates as well as viscosities can be read-off from various corresponding spectral functions. As well-known that the spectral function is hidden in the lattice-computable ... More
Presented by Prof. Heng-Tong DING on 27 Jul 2018 at 5:30 PM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
The increasing unbalance between computing capabilities of individual nodes and internode communication makes it highly desirable for any Lattice QCD algorithm to minimize the amount of off-node communication. One of the relatively new methods for this is the 'split-grid' or 'split-domain', where data is rearranged within the running of a single binary, so that the routines which requires si ... More
Presented by Dr. Chulwoo JUNG on 24 Jul 2018 at 6:45 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We present results of our technique of dynamic stabilisation (DS) applied to complex Langevin simulations of QCD in the heavy-dense limit and with staggered quarks. We show that DS is able to keep simulations stable, providing results compatible with Monte-Carlo simulations, where the latter is applicable.
Presented by Dr. Felipe ATTANASIO on 23 Jul 2018 at 2:40 PM
Session: Hadron Structure
Track: Hadron Structure
I present the current status of the HVP calculation for the muon anomalous magnetic moment by the RBC and UKQCD collaborations both for a pure lattice and a combined lattice+R-ratio calculation. I will report on our recent work [1801.07224] and on progress towards the reduction of statistical and systematic uncertainties.
Presented by Christoph LEHNER on 27 Jul 2018 at 2:00 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
The Yang-Mills gradient flow can be used to calculate the strange quark scalar content in nucleons using Lattice QCD. Given the renormalization properties of flowed operators, the procedure promises a reduction of the uncertainties in the determination of the spin independent (SI) elastic cross section of dark matter models involving WIMP-nucleon interactions. Chiral symmetry and a small flow-tim ... More
Presented by Jose Gabriel REYES-RIVERA on 27 Jul 2018 at 2:00 PM
Session: Hadron Structure
Track: Hadron Structure
We present preliminary results for strange form factors of the nucleon computed on the CLS ensembles with $N_f=2+1$ flavours of O($a$)-improved Wilson fermions. Our calculations are performed at two values of the lattice spacing ($a \in \{0.064, 0.086\} \,\mathrm{fm}$) at a pion mass of $280 \,\mathrm{MeV}$. The determination of strange form factors proceeds by computing quark-disconnected diagram ... More
Presented by Mr. Jonas WILHELM on 25 Jul 2018 at 4:50 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The static potential V(r) between a static quark and a static antiquark separated by a distance r is defined as the energy of the ground state of this system. As a consequence of confinement, the energy between the quark-antiquark pair is contained inside a color flux tube, the so called string. As soon as the energy is high enough, the gluonic string connecting the quarks will break due to pair ... More
Presented by Ms. Vanessa KOCH on 24 Jul 2018 at 2:00 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
In the last decade, a significant experimental progress has been achieved in studying the heavy-light meson spectroscopy. Heavy-light mesons composed of one heavy quark Q and a light quark q are useful in understanding the strong interactions in the non perturbative regime. Experiments like LHCb, Babar etc are providing many new states which are being added to their spectroscopy. But the informat ... More
Presented by Ms. Pallavi GUPTA on 24 Jul 2018 at 3:20 PM
Session: Hadron Structure
Track: Hadron Structure
Direct lattice computation of the key measures of hadron structure such as the form factors, parton distribution functions, quark distribution amplitudes have always been challenging. With current enormous experimental efforts at JLab (with its 12 GeV upgrade), COMPASS in CERN, RHIC-spin and at a future EIC, it is now crucial to test and exploit the newly proposed lattice QCD ideas in hadron struc ... More
Presented by Dr. Bipasha CHAKRABORTY on 24 Jul 2018 at 2:20 PM
Session: Weak Decays and Matrix Elements
Track: Hadron Spectroscopy and Interactions
We report a direct lattice calculation of both the I=0 and 2 pi-pi scattering phase shifts using G-parity boundary conditions on an ensemble of $32^3\times64$ gauge configurations at physical quark mass. This extends an earlier calculation of the RBC/UKQCD Collaboration by including additional operators and using non-zero center-of-mass momenta. We apply the generalized eigenvalue treatment to t ... More
Presented by Mr. Tianle WANG on 26 Jul 2018 at 11:20 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study correlation functions of the energy-momentum (EM) tensor in Nf=2+1 full QCD for the sake of QGP viscosities. The viscosity is given by three steps on lattice: (1) calculate two point correlation functions of the energy-momentum tensor, (2) derive the spectral function from the correlation function, (3) applying the Kubo's formula the viscosity is related to the spectral function. Ho ... More
Presented by Prof. Yusuke TANIGUCHI on 26 Jul 2018 at 9:10 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
This talk is an overview of our recent investigations of supersymmetric and near conformal gauge theories. We have studied extensively $\mathcal{N}=1$ super Yang-Mills theory, most recently with the gauge group SU(3). In addition we have investigated theories that show indications for a conformal behaviour with an infrared fixed point. More recently we have included a mixed fundamental and adjoint ... More
Presented by Dr. Georg BERGNER on 27 Jul 2018 at 5:10 PM
Type: Poster Session: Poster reception
Track: Physics Beyond the Standard Model
We study a model of four reduced staggered fermions transforming in the bifundamental representation of an SU(2)xSU(2) symmetry group. Single site mass terms are prohibited by this symmetry but a particular four fermi term is allowed. We gauge one of the SU(2) subgroups and examine the phase structure of the model. We find evidence that the theory forms a symmetric four fermion condensate at str ... More
Presented by Nouman BUTT on 24 Jul 2018 at 6:45 PM
Type: Plenary Session: Plenary
Track: Hadron Structure
The current status of calculations of simple nucleon structure observables, such as the axial charge, will be reviewed. Recent calculations have produced steadily better control over the standard sources of systematic uncertainty, and there are now multiple groups doing calculations with near-physical quark masses. A major challenge is the combination of an exponentially decaying signal-to-noise r ... More
Presented by Dr. Jeremy GREEN on 27 Jul 2018 at 9:30 AM
Session: Applications beyond QCD
Track: Applications Beyond QCD
We present a study of the relative lattice spacing of different ensembles in the Euclidean dynamical triangulations approach to quantum gravity. We study the quantum fluctuations of the semiclassical backgrounds about de Sitter space following a similar analysis in causal dynamical triangulations and show how this can be used to determine the relative lattice spacing in our analysis. The agreeme ... More
Presented by Jack LAIHO on 23 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The QCD pressure at non-zero chemical potential mu is typically obtained via a Taylor expansion in mu. The Taylor coefficients are traces of powers of the inverse Dirac matrices, which are computed using many noisy estimators. Here, we present an alternative based on the Cauchy Residue Theorem and discuss its merits for the Taylor coefficients.
Presented by Prof. Benjamin JAEGER on 27 Jul 2018 at 2:40 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We present results for lattice QCD in the limit of infinite gauge coupling on a discrete spatial but continuous Euclidean time lattice. A worm type Monte Carlo algorithm is applied in order to sample two-point functions which gives access to the measurement of mesonic temporal correlators. The continuous time limit, based on sending Nτ→∞ and the bare anistotropy to infinity while fixing the ... More
Presented by Mr. Marc KLEGREWE on 27 Jul 2018 at 4:50 PM
Type: Plenary Session: Plenary
Track: Theoretical Developments
The term Tensor Network States (TNS) has become a common one in the context of numerical studies of quantum many-body problems. It refers to a number of families that represent different ansatzes for the efficient description of the state of a quantum many-body system. The first of these families, Matrix Product States (MPS), lies at the basis of Density Matrix Renormalization Group methods, which ... More
Presented by Dr. Mari Carmen BANULS on 28 Jul 2018 at 10:15 AM
Session: Theoretical Developments
Track: Theoretical Developments
The tensor renormalization group attracts great attention as a new numerical method because it is free of the sign problem. In addition to this striking feature, it has also an attractive aspect as a coarse-graining of space-time; that is to say, the computational cost scales logarithmically with the space-time volume. This fact allows us to aggressively approach the thermodynamic limit. While tak ... More
Presented by Mr. Ryo SAKAI on 26 Jul 2018 at 9:30 AM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We report on a calculation of the charmonium contribution to the decay $B \rightarrow Kll$ using lattice simulations with 2+1 flavors of Mobius domain wall fermions. We focus on the region of $q^2$ below the $J/\psi$ resonance and test the factorization approximation to estimate the amplitude.
Presented by Mr. Katsumasa NAKAYAMA on 27 Jul 2018 at 2:40 PM
Session: Algorithms and Machines
Track: Algorithms and Machines
In hybrid Monte Carlo evolution, by imposing a physical gauge condition, simple Fourier acceleration can be used to generate conjugate momenta and potentially reduce critical slowing down. This modified gauge evolution algorithm does not change the gauge-independent properties of the resulting gauge field configurations. We describe this algorithm and present results from our first numerical ex ... More
Presented by Mr. Yidi ZHAO on 23 Jul 2018 at 2:20 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
Using HISQ $N_f=2+1+1$ MILC ensembles at five different lattice spacings, including four ensembles with physical quark masses, we perform the most precise computation to date of the $K\to\pi\ell\nu$ vector form factor at zero momentum transfer. This is the first calculation that includes the dominant finite-volume effects, as calculated in chiral perturbation theory at next-to-leading order. Our r ... More
Presented by Prof. Aida EL-KHADRA on 25 Jul 2018 at 2:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Chiral Random Matrix Theory has proven to describe the spectral prop- erties of low temperature QCD very well. However, at temperatures above the chiral symmetry restoring transition it can not provide a global descrip- tion. The level-spacing distribution in lower part of the spectrum of the Dirac operator is Poisson-like. The eigenmodes are localized in space-time and separated from the res ... More
Presented by Mr. Lukas HOLICKI on 27 Jul 2018 at 3:20 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Structure
We present an update on the direct position-space method for calculating slopes of from factors from lattice QCD.Momentum-space derivatives of matrix elements can be related to their coordinate-space moments through the Fourier transform. We derive these expressions as a function of momentum transfer $Q^2$ for asymptotic in/out states consisting of a single hadron. We calculate corrections to the ... More
Presented by Chia Cheng CHANG on 23 Jul 2018 at 4:50 PM
Session: Theoretical Developments
Track: Theoretical Developments
We investigate the phase structure of the 2-d U(1) gauge-Higgs model at non-vanishing topological angle $\theta$. The sign problem arising from the topological term is avoided by invoking a dual representation of the gauge-Higgs model. This allows us to observe a 1st order transition in the topological charge at the symmetrical point $\theta=\pi$. By using the Villain action to discretize the gaug ... More
Presented by Mr. Daniel GOESCHL on 25 Jul 2018 at 2:40 PM
Type: Parallel Session: Chiral Symmetry
Track: Chiral Symmetry
We report on measurements of the eta^prime mass on some of the 2+1 flavor DWF ensembles that have been generated by the RBC and UKQCD collaborations. We investigate the accuracy of our statistical errors, given the observed evolution of topological modes on these ensembles.
Presented by Mr. Duo GUO on 25 Jul 2018 at 4:10 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
The region of the Columbia plot with two light quark flavors is not yet conclusively understood. Non-perturbative effects, e.g. the magnitude of the anomalous U(1) axial symmetry breaking decides on the nature of the phase transition in this region. We report on our study of this region of the Columbia plot using lattice techniques. We use gauge ensembles generated within the Highly Improved Stag ... More
Presented by Mr. Lukas MAZUR on 24 Jul 2018 at 2:20 PM
Session: Hadron Structure
Track: Hadron Structure
We report on our ongoing project to determine the leading-order hadronic vacuum polarisation contribution to the muon $g-2$, using ensembles with $N_f=2+1$ flavours of O($a$) improved Wilson quarks generated by the CLS effort, with pion masses down to the physical value. We employ O($a$) improved versions of the local and conserved vector currents to compute the contributions of the light, st ... More
Presented by Prof. Hartmut WITTIG on 27 Jul 2018 at 4:50 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
We apply a recently developed dilaton-pion effective field theory for asymptotically free gauge theories near the conformal window to the SU(3) gauge theory with $N_f=8$ fermions in the fundamental representation. Numerical data for this theory suggests the existence of a large-mass regime, where the fermion mass is not small but nevertheless the effective theory is applicable because of the ... More
Presented by Prof. Maarten GOLTERMAN on 26 Jul 2018 at 11:20 AM
Type: Parallel Session: Hadron Structure
Track: Hadron Structure
We present a preliminary study of the leading hadronic contribution to the running of the electroweak mixing angle $\theta_W$. The running is extracted from the correlation function of the electromagnetic current with the (vector part of the) weak neutral current using the Lorentz-covariant coordinate-space method recently introduced by Meyer. Both connected and disconnected contributions have bee ... More
Presented by Dr. Marco CÈ on 27 Jul 2018 at 3:40 PM
Session: Theoretical Developments
Track: Theoretical Developments
We report on our computation of the perturbative running of the 't Hooft coupling in a pure gauge SU(N) theory with twisted boundary conditions. The computation was performed using gradient flow methods in four dimensions, in the continuum, and using dimensional regularisation. The coupling is defined in terms of the energy density of the flow fields at a scale given by a particular combination of ... More
Presented by Mr. Eduardo IBANEZ BRIBIAN on 27 Jul 2018 at 4:30 PM
Type: Poster Session: Poster reception
Track: Physics Beyond the Standard Model
We consider 1+1-dimensional maximally supersymmetric Yang–Mills theory (SYM) at large N and strong ’t Hooft coupling which is dual to D1 branes. One can have different tori based on the expansion of the gauge links in the moduli space, which is required to target the correct continuum theory. In our previous work, we explored a special skewed torus corresponding to A2* geometry. Here, we will ... More
Presented by Mr. Raghav Govind JHA on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
Quark line disconnected matrix elements of an operator, such as the axial current, are difficult to compute on the lattice. The standard method uses a stochastic estimator of the operator, which is very noisy. We discuss and further develop our alternative approach using the Feynman-Hellmann theorem which involves only evaluating two-point correlation functions. This is applied to computing ... More
Presented by Dr. Roger HORSLEY on 25 Jul 2018 at 5:10 PM
Type: Plenary Session: Plenary
Track: Theoretical Developments
Electron-Ion Collider (EIC) is the highest priority for new construction in US nuclear science community and will likely to start physics program in about 5-10 years from now. EIC enables to make detailed studies of the parton structure of nucleons and nuclei in unprecedented accuracy and kinematic domain. How to compute the EIC observables, namely various parton distributions and fragmentations, ... More
Presented by Prof. Xiangdong JI on 27 Jul 2018 at 9:00 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
Lattice QCD at strong coupling has long been studied in a dual representation to circumvent the finite baryon density sign problem. Recent results that established the non-perturbative functional dependence between the bare anisotropy and the physical anisotropy a/a_t in the chiral limit are now extended to finite quark mass. We discuss the consequences of the anisotropy callibration to the equati ... More
Presented by Dr. Unger WOLFGANG on 27 Jul 2018 at 4:30 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We present lattice calculations of the equation of state of pure SU(2) gauge theory by using the gradient flow. The scale-setting of lattice parameter has been carried, and we propose a reference scale t0 satisfying t2E=0.1 for SU(2) gauge theory. This reference value is fixed by a natural scaling-down of the t0 scale for the SU(3) based on perturbative analysis. We also show the thermodynamic qua ... More
Presented by Mr. Takehiro HIRAKIDA on 26 Jul 2018 at 9:30 AM
Session: Algorithms and Machines
Track: Algorithms and Machines
A simple minded approach to implement three discretizations of the Dirac operator (Brillouin, Wilson, staggered) on two architectures (KNL and core_i7) is presented. The idea is to use a high-level compiler along with OpenMP parallelization and SIMD pragmas, but to stay away from cache-line optimization and/or assembly-tuning. The implementation is for Nv right-hand-sides, and this extra index is ... More
Presented by Dr. Stephan DURR on 23 Jul 2018 at 5:10 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present a study on ab-initio calculations of three-neutron correlators, and more generally, three-nucleon correlators, from Lattice QCD. Baryon blocks have been employed to simulate two nucleon systems in the past. We extend the method to three nucleons. In addition, we use automatic code generation to provide more flexibility and allow for easy inclusion of additional channels in the future wh ... More
Presented by Mr. Jan-Lukas WYNEN on 27 Jul 2018 at 5:50 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study the topological charge in $N_f=2$ QCD at finite temperature using Mobius domain-wall fermions with reweighting to ovelap fermions. The susceptibility $\chi_t$ of the topological charge is studied in the high temperature phase with varying quark mass. Last year, we reported on a strong suppression of the susceptibility, observed below a certain value of the quark mass on a fixed spat ... More
Presented by Yasumichi AOKI on 24 Jul 2018 at 2:40 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
At high temperatures, the topological susceptibility of QCD becomes relevant for the properties of axion dark matter. However, the strong suppression of non-zero topological sectors causes ordinary sampling techniques to fail, since fluctuations of the topological charge can only be measured reliably if enough tunneling events between sectors occur. We present a new method to circumvent this probl ... More
Presented by Mr. P. Thomas JAHN on 24 Jul 2018 at 3:00 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We report our study on the properties of the topological structures present in the QCD medium just above the chiral crossover transition. We use dynamical domain wall fermion configurations on lattices of size 32^3x8, used earlier in [1] to calculate the crossover transition temperature Tc in QCD, and detect the topological structures through the zero modes of the overlap operator. In particular, ... More
Presented by Mr. Rasmus LARSEN on 24 Jul 2018 at 3:20 PM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We study two-color QCD with nonzero chemical potential using Iwasaki gauge and Wilson fermion action. The two-color gauge theory coupled to an even number of fundamental fermions does not suffer from the sign problem because the fermion transforms in a real representation. To perform the simulation even in high chemical potential regime, as in earlier publications, we introduce a diquark sour ... More
Presented by Etsuko ITOU on 26 Jul 2018 at 9:50 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
At finite density, lattice simulations are hindered by the well-known sign problem: for finite chemical potentials, the QCD action becomes complex and the Boltzmann weight e^-S cannot be interpreted as a probability distribution to determine expectation values by Monte Carlo techniques. Different workarounds have been devised to study the QCD phase diagram, but their application is mostly limited ... More
Presented by Kevin ZAMBELLO on 23 Jul 2018 at 4:10 PM
Session: Theoretical Developments
Track: Theoretical Developments
Lattice QCD in a color singlet representation has been studied since decades in the limit $\beta\to 0$. In this limiting case it is possible to integrate out analytically the partition function at finite density which is then written in terms of dual, integer, degrees of freedom representing mesons and baryons. The partition function can be then sampled by means of Worm algorithms. It turned out t ... More
Presented by Mr. Giuseppe GAGLIARDI on 25 Jul 2018 at 2:00 PM
Type: Parallel Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
The quark-chrom EDM (qCEDM) is a dimension 5 operator parametrizing at low energy BSM contributions to a non-vanishing EDM. We discuss the implementation of the qCEDM with the gradient flow and show preliminary results for the flow-time dependence of the CP-violating mixing angle $\alpha_N$ induced by the qCEDM between nucleon states. These results are computed on the $N_f=2+1$ coarse lattice $1 ... More
Presented by Dr. Jangho KIM on 24 Jul 2018 at 2:20 PM
Type: Poster Session: Poster reception
Track: Algorithms and Machines
We present a recently started project of a new implementation of a C++ code-base to perform lattice QCD calculations. As a first step, we have implemented a Multi-Hit Metropolis algorithm for generating configurations in Yang-Mills theory and a third order Runge-Kutta scheme for applying the Gradient Flow to the gauge fields. We performed tests of the autocorrelation time of the energy ... More
Presented by Mr. Giovanni PEDERIVA on 24 Jul 2018 at 6:45 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
Lattice calculations of RI'(S)MOM renormalization constants typically generate lots of data for gauge-fixed n-point functions. We reuse this data and determine the full nonperturbative tensor structure of the underlying vertices. They are a crucial input for calculations of hadronic observables formulated as bound-state problems in QCD. We show first data for the simplest fermionic bilinears and c ... More
Presented by Dr. Andre STERNBECK on 25 Jul 2018 at 4:50 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
We present an exploratory study of leading isospin breaking effects in mesonic masses using $O(a)$ improved Wilson fermions with open boundaries. Isospin symmetry is explicitly broken by distinct masses and electric charges of the up and down quarks. In order to be able to make use of existing isosymmetric QCD gauge ensembles we apply reweighting techniques. The path integral describing QCD+QED is ... More
Presented by Mr. Andreas RISCH on 24 Jul 2018 at 4:30 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Numerical evidence for a new dynamical mechanism of elementary particle mass generation has been found by lattice simulation in a simplified SU(3) gauge model where a SU(2) doublet of strongly interacting fermions is coupled to a complex scalar field doublet via a Yukawa and a Wilson-like term. We point out that if, as a next step towards the construction of a realistic beyond-the-Standard-Model ... More
Presented by Prof. Roberto FREZZOTTI on 23 Jul 2018 at 3:20 PM
Session: Standard Model Parameters and Renormalization
Track: Standard Model Parameters and Renormalization
We construct a concrete strategy to implement the non-perturbative renormalization of the $\Delta S = 1$ four-quark operators, which are associated with $K \to \pi\pi$ matrix elements. These non-perturbative methods can be used to determine the Wilson coefficients for the 3-flavor theory, avoiding a significant source of systematic uncertainty that arises from perturbative matching through the cha ... More
Presented by Dr. Masaaki TOMII on 26 Jul 2018 at 9:30 AM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The study of strong scattering in Lattice QCD is enabled by the use of the Luescher method, which defines a mapping between the two body spectrum in the finite volume and the infinite volume scattering amplitude.This talk focuses on the study of $\pi N$ scattering in $P$-wave and $I=\frac{3}{2}$, where the $\Delta$ resonance resides. We use $N_f=2+1$ flavors of tree-level improved Wilson-clover ... More
Presented by Mr. SRIJIT PAUL on 27 Jul 2018 at 4:50 PM
Session: Hadron Spectroscopy and Interactions
Track: Hadron Spectroscopy and Interactions
The study of strong scattering in Lattice QCD is enabled by the use of the Luescher method, which defines a mapping between the two body spectrum in the finite volume and the infinite volume scattering amplitude. It however requires full and precise knowledge of the spectrum in a given moving frame and irreducible representation. In this project we investigate the $\Delta$ (1232) resonance in ... More
Presented by Mr. Giorgio SILVI on 27 Jul 2018 at 4:30 PM
Type: Poster Session: Poster reception
The low-lying hadron spectrum has been of tremendous phenomenological significance in resolving the nature of quark masses in strong interaction dynamics. In particular, the pseudoscalar mesons provide the foundation of the framework of chiral perturbation theory, the low-energy effective theory of QCD. Modern lattice calculations of pure QCD now provide excellent precision in the resolution of qu ... More
Presented by Prof. Ross YOUNG on 24 Jul 2018 at 6:45 PM
Session: Hadron Structure
Track: Hadron Structure
The transverse spin structure of matter is a subject of research that has not been thoroughly explored experimentally, providing the opportunity to produce key insight from lattice QCD. We present the latest results of the transverse spin densities of the octet baryons through analysis of electromagnetic and tensor form factors. We employ $N_f=2+1$ flavours of $\mathcal{O}(a)$-improved Wilson ferm ... More
Presented by Mr. Jacob BICKERTON on 25 Jul 2018 at 3:00 PM
Session: Applications beyond QCD
Track: Applications Beyond QCD
Non-abelian gauge theories have a complex vacuum structure which has well-known dynamical consequences. The prototypical example is given by $SU(2)$ sphalerons and their potential role in baryogenesis. Transitions between topologically inequivalent vacua can produce some irreversible net amount of chiral charge. At a first glance, it does not seem that similar effects may be obtained with Abeli ... More
Presented by Mr. Adrien FLORIO on 23 Jul 2018 at 3:00 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We update the calculation of $B \to D^\ast \ell \nu$ form factor at zero-recoil using the Oktay-Kronfeld (OK) action for bottom and charm quarks. Heavy quark action is nonperturbatively tuned. The flavor changing currents are improved to $\mathcal{O}(\lambda\approx \Lambda_{QCD}/2m_Q)$, $Q=b,c$ at tree-level in the HQET power counting. We use the HISQ action for the light spectator quark with seve ... More
Presented by Dr. Sungwoo PARK on 27 Jul 2018 at 2:40 PM
Session: Weak Decays and Matrix Elements
Track: Weak Decays and Matrix Elements
We provide an update on the RBC & UKQCD lattice calculation of the measure of Standard Model direct CP-violation in kaon decays, \epsilon'
Presented by Dr. Christopher KELLY on 26 Jul 2018 at 11:40 AM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
I present updated spectroscopy results from the LSD collaboration on SU(3) gauge theory with $N_f=8$ degenerate fermions in the fundamental representation, using nHYP-smeared staggered fermions. The new results include added statistics, a more sophisticated systematic error analysis, and the use of joint fits to stabilize estimates of the $0^{++}$ scalar meson mass. We find persistent evide ... More
Presented by Prof. Ethan NEIL on 26 Jul 2018 at 12:00 PM
Session: Hadron Structure
Track: Hadron Structure
We update the nucleon axial, electric, and magnetic form factors obtained from Clover-on-HISQ lattice formulation. Previous results from the $2+1+1$-flavor HISQ ensembles are extended by analyzing more ensembles to cover $a \approx 0.15, 0.12, 0.09, 0.06\,\mathrm{fm}$, $M_\pi \approx 310, 220, 130\,\mathrm{MeV}$, and $ 3.3 < M_\pi L < 5.5$. All data are bias corrected with the AMA method. With hig ... More
Presented by Dr. Yong-Chull JANG on 26 Jul 2018 at 9:30 AM
Session: Vacuum Structure and Confinement
Track: Vacuum Structure and Confinement
This presentation examines the structure of centre vortices in Monte-Carlo generated gauge-field configurations using modern visualization techniques. We'll begin with a brief review of how centre vortices underpin dynamical chiral symmetry breaking and how their removal restores chiral symmetry. Centre vortices are identified through gauge transformations maximizing the centre of the gauge gr ... More
Presented by Prof. Derek LEINWEBER on 24 Jul 2018 at 4:10 PM
Session: Theoretical Developments
Track: Theoretical Developments
Dual description of SU(2) lattice gauge theory in 2+1 dimensions is shown to be the theory of interacting gauge invariant ‘abelian like’ electric loops. The Gauss law is solved exactly to construct the Hilbert space of the gauge invariant theory using the Schwinger boson representation. This is achieved by envisaging what is called the ‘splitting of a point'. Such a 'point split' lattice all ... More
Presented by Dr. Sreeraj T P on 25 Jul 2018 at 2:20 PM
Session: Plenary
Presented by Zohreh DAVOUDI on 25 Jul 2018 at 11:45 AM
Session: Nonzero Temperature and Density
Track: Nonzero Temperature and Density
We formulate a world-line approach to study few body physics on a space-time lattice and develop a worm type algorithm to extract the low lying energy levels. We show that our formulation is efficient for studying non-relativistic spin-half fermions with both attractive and repulsive interactions and in the presence of mass imbalance, especially in one spatial dimension. Recently, such systems hav ... More
Presented by Hershdeep SINGH on 24 Jul 2018 at 4:30 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
Equivariant BRST (eBRST) SU(2) gauge theory involves gauge fixing in the SU(2)/U(1) coset space leaving the subgroup U(1) gauge invariant. This can be taken as an alternative formulation of SU(2) lattice gauge theory that uses gauge-fixing, evading the no-go theorem by Neuberger preventing the use of standard BRST. Results will be presented for our numerical simulation of the eBRST gauge theory, g ... More
Presented by Mr. Mugdha SARKAR on 24 Jul 2018 at 3:20 PM
Session: Physics beyond the Standard Model
Track: Physics Beyond the Standard Model
I will present an update on our calculations of nEDM due to the quark and gluon chromo-EDM operators, as well as the QCD Theta-term with which these mix. The calculations are being done by extrapolating to zero momentum transfer the F3 form factor of a vector current calculated using valence and disconnected Wilson-clover quarks on HISQ background configurations generate by the MILC collaboration ... More
Presented by Dr. Tanmoy BHATTACHARYA on 23 Jul 2018 at 2:40 PM