Dr
Krzysztof Cichy
(Adam Mickiewicz University)

7/23/18, 2:00 PM

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...

Ms
Aurora Scapellato
(University of Cyprus - University Of Wuppertal)

7/23/18, 2:20 PM

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...

Dr
Yong Zhao
(Massachusetts Institute of Technology)

7/23/18, 2:40 PM

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...

Yibo Yang
(Michigan State University)

7/23/18, 3:00 PM

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...

Dr
Yu-Sheng Liu
(Tsung-Dao Lee Institute)

7/23/18, 3:20 PM

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...

Joseph Karpie
(William and Mary)
, Dr
Savvas Zafeiropoulos
(Universitaet Heidelberg)

7/23/18, 4:10 PM

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...

Joseph Karpie
(William and Mary)
, Dr
Savvas Zafeiropoulos
(Universitaet Heidelberg)

7/23/18, 4:30 PM

Hadron Structure

Jian Liang
(University of Kentucky)

7/23/18, 4:50 PM

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...

Mr
Kim Somfleth
(CSSM Adelaide University)

7/23/18, 5:10 PM

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...

Raza Sufian
(Jef)

7/24/18, 2:00 PM

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...

Dr
Bipasha Chakraborty
(Jefferson Lab)

7/24/18, 2:20 PM

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...

Mr
Rui Zhang
(Institute of Theoretical Physics, Chinese Academy of Sciences)

7/24/18, 2:40 PM

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...

Dr
Santanu Mondal
(National Chiao-Tung University)

7/24/18, 3:00 PM

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...

Dr
Piotr Korcyl
(Jagiellonian University and University of Regensburg)

7/24/18, 3:20 PM

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...

Dr
Jianhui Zhang
(University of Regensburg)

7/24/18, 4:10 PM

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...

Dr
Nikhil Karthik
(BNL)

7/24/18, 4:30 PM

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...

Charles Shugert
(Stony Brook University and Brookhaven National Lab)

7/24/18, 4:50 PM

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 $0.061$...

Mr
Guerrero Juan
(Hampton University/Jefferson Lab)

7/25/18, 2:00 PM

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...

Zohreh Davoudi
(University of Maryland)

7/25/18, 2:20 PM

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...

Dr
Philipp Wein
(Universität Regensburg)

7/25/18, 2:40 PM

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...

Mr
Jacob Bickerton
(University of Adelaide)

7/25/18, 3:00 PM

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...

Michael Engelhardt
(NMSU)

7/25/18, 3:20 PM

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...

Mr
Lukas Varnhorst
(University of Wuppertal)

7/25/18, 4:10 PM

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.

Dr
Christian Hoelbling
(Wuppertal University)

7/25/18, 4:30 PM

Hadron Structure

We present recent progress in the determination of nucleon sigma terms by the BMW collaboration. In this talk physical results are presented.

Mr
Jonas Wilhelm
(University of Mainz - Institut for Nuclear Physics)

7/25/18, 4:50 PM

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...

Dr
Roger Horsley
(University of Edinburgh)

7/25/18, 5:10 PM

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...

Dr
Boram Yoon
(Los Alamos National Laboratory)

7/26/18, 8:30 AM

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...

Prof.
Sergey Syritsyn
(Stony Brook University (SUNY))

7/26/18, 8:50 AM

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...

Mr
Yin Lin
(University of Chicago)

7/26/18, 9:10 AM

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...

Dr
Yong-Chull Jang
(Brookhaven National Laboratory)

7/26/18, 9:30 AM

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...

Prof.
Yoshinobu Kuramashi
(University of Tsukuba)

7/26/18, 9:50 AM

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...

Dr
Christos Kallidonis
(Stony Brook University)

7/26/18, 10:10 AM

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...

Dr
Arjun Gambhir
(Lawrence Livermore National Laboratory)

7/26/18, 11:00 AM

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...

Gen Wang
(University of Kentucky)

7/26/18, 11:20 AM

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...

Shigemi Ohta
(IPNS, KEK)

7/26/18, 11:40 AM

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.

Dr
Konstantin Ottnad
(University of Mainz)

7/26/18, 12:00 PM

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...

Dr
David Richards
(Jefferson Laboratory)

7/26/18, 12:20 PM

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...

Dr
Rajan Gupta
(Los Alamos National Lab)

7/26/18, 12:40 PM

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.

Christoph Lehner
(BNL)

7/27/18, 2:00 PM

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.

Dr
Aaron Meyer
(Brookhaven National Laboratory)

7/27/18, 2:20 PM

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...

Dr
Vera Guelpers
(University of Southampton)

7/27/18, 2:40 PM

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...

Dr
Mattia Bruno
(BNL)

7/27/18, 3:00 PM

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...

James Zanotti
(University of Adelaide)

7/27/18, 3:20 PM

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...

Dr
Marco Cè
(Helmholtz-Institut Mainz, Johannes Gutenberg-Universität Mainz)

7/27/18, 3:40 PM

Hadron Structure

Parallel

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...

41.
HISQ light quark hadronic vacuum polarization contribution to the muon anomalous magnetic moment

Thomas Blum
(University of Connecticut)

7/27/18, 4:30 PM

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...

Prof.
Hartmut Wittig
(Johannes Gutenberg Universität)

7/27/18, 4:50 PM

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...

Mr
Davide Giusti
(Università degli Studi Roma Tre and INFN - Sezione di Roma Tre)

7/27/18, 5:10 PM

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...

Taku Izubuchi
(Brookhaven National Laboratory)

7/27/18, 5:30 PM

Hadron Structure

Parallel

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...

Prof.
Martha Constantinou
(Temple University)

7/27/18, 5:50 PM

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.