Dimitra Pefkou
(Student at William and Mary)
7/23/18, 4:10 PM
Hadron Spectroscopy and Interactions
Parallel
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 in...
Dr
Maxim Mai
(The George Washington University)
7/23/18, 4:30 PM
Hadron Spectroscopy and Interactions
Parallel
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...
Chia Cheng Chang
(iTHEMS RIKEN)
7/23/18, 4:50 PM
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...
Dr
Roman Höllwieser
(Bergische Universität Wuppertal)
7/23/18, 5:10 PM
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...
Ms
Vanessa Koch
(Trinity College Dublin)
7/24/18, 2:00 PM
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...
Mr
Christian Reisinger
(Goethe Universität Frankfurt am Main, Institut für Theoretische Physik)
7/24/18, 2:20 PM
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...
Dr
Zhihui Guo
(Hebei Normal University)
7/24/18, 2:40 PM
Hadron Spectroscopy and Interactions
Parallel
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...
Dr
Ning Li
(NSCL/FRIB, Michigan State University)
7/24/18, 3:00 PM
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...
Ms
Pallavi Gupta
(Thapar University)
7/24/18, 3:20 PM
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...
Cheng Tu
(University of Connecticut)
7/24/18, 4:10 PM
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...
Mr
Andreas Risch
(Institute for Nuclear Physics, University of Mainz)
7/24/18, 4:30 PM
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...
Dr
Eigo Shintani
(RIKEN-CCS)
7/24/18, 4:50 PM
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...
Dr
Oliver Baer
(Humboldt University Berlin)
7/25/18, 2:00 PM
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...
Mr
Tobias Schulz
(University of Mainz)
7/25/18, 2:20 PM
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...
Mr
Colin Egerer
(William and Mary)
7/25/18, 2:40 PM
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...
Daniel Hoying
7/25/18, 3:00 PM
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...
Dr
Luka Leskovec
(University of Arizona)
7/25/18, 3:20 PM
Hadron Spectroscopy and Interactions
Parallel
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...
Andre Walker-Loud
(LBNL)
7/25/18, 4:10 PM
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...
Mr
James Harrison
(University of Southampton)
7/25/18, 4:30 PM
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...
Dr
Andre Sternbeck
(University of Jena)
7/25/18, 4:50 PM
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...
Mr
Yunheng Ma
(Institute of High Energy Physics, Chinese Academy of Sciences)
7/25/18, 5:10 PM
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...
Mr
Daniel Darvish
(Carnegie Mellon University)
7/26/18, 8:30 AM
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.
Ruairí Brett
(Carnegie Mellon University)
7/26/18, 8:50 AM
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...
Dr
Ferenc Pittler
(HISKP BONN)
7/26/18, 9:10 AM
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.
Mr
Jesus Gumaro Rendon Suzuki
(University of Arizona)
7/26/18, 9:30 AM
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...
Mr
Gavin Cheung
(University of Cambridge)
7/26/18, 9:50 AM
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...
Alessandro Baroni
(University of South Carolina)
7/26/18, 10:10 AM
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...
Prof.
Stephen Sharpe
(University of Washington)
7/26/18, 11:00 AM
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...
Takeshi Yamazaki
(Univerity of Tsukuba)
7/26/18, 11:20 AM
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...
Dr
Yusuke Namekawa
(University of Tsukuba)
7/26/18, 11:40 AM
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...
Prof.
Keh-Fei Liu
(University of Kentucky)
7/26/18, 12:00 PM
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...
Dr
Jacob Fallica Fallica
(University of Kentucky)
7/26/18, 12:20 PM
Hadron Spectroscopy and Interactions
Parallel
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...
Dr
Andrew Hanlon
(Helmholtz-Institut Mainz, JGU)
7/26/18, 12:40 PM
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...
Mr
Salvatore Cali
(University of Wuppertal)
7/27/18, 2:00 PM
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...
Dr
Andrew Lytle
(University of Glasgow)
7/27/18, 2:20 PM
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...
Dr
Utku Can
(RIKEN)
7/27/18, 2:40 PM
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...
Dr
Xiao-Yu Guo
(GSI Helmholzzentrum)
7/27/18, 3:00 PM
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...
Dr
Stefano Piemonte
(University of Regensburg)
7/27/18, 3:20 PM
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...
Ms
Ursa Skerbis
(Jozef Stefan Institute, Ljubljana, Slovenija)
7/27/18, 3:40 PM
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...
Mr
Giorgio Silvi
(Forschungszentrum Jülich - University of Wuppertal)
7/27/18, 4:30 PM
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...
Mr
SRIJIT PAUL
(The Cyprus Institute)
7/27/18, 4:50 PM
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...
Dr
Takumi Iritani
(RIKEN)
7/27/18, 5:10 PM
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...
Takumi Doi
(RIKEN)
7/27/18, 5:30 PM
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 method.
Mr
Jan-Lukas Wynen
(Forschungszentrum Jülich)
7/27/18, 5:50 PM
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...
Mr
Takuya Sugiura
(RCNP, Osaka University)
7/27/18, 6:10 PM
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...