Conveners
Hadron Structure
- David Richards (Jefferson Lab)
Hadron Structure
- There are no conveners in this block
Hadron Structure
- Sara Collins (University of Regensburg)
Hadron Structure
- Michael Engelhardt
Hadron Structure
- Shigemi Ohta (KEK High Energy Accelerator Organization)
Hadron Structure
- Christopher Sachrajda (University of Southampton)
- Oliver Baer (Humboldt University Berlin, Germany)
Hadron Structure
- Luigi Del Debbio (The University of Edinburgh (GB))
Hadron Structure
- James Zanotti (University of Adelaide)
Hadron Structure
- Raza Sufian (William & Mary / Jefferson Lab)
Hadron Structure
- Yi-Bo Yang (CAS)
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Mr Lorenzo Barca (Universitรคt Regensburg)7/26/21, 1:00โฏPMHadron StructureOral presentation
Excited state contamination is one of the most challenging sources of systematics to tackle in the determination of nucleon matrix elements and form factors.
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The signal-to-noise problem prevents one from considering large source-sink time separations.
Instead, state-of-the-art analyses consider multi-state fits.
Excited state contributions to the correlation functions are particularly... -
Roger Horsley (University of Edinburgh)7/26/21, 1:15โฏPMHadron StructureOral presentation
Using an SU(3) flavour symmetry breaking expansion between the strange and light quark masses, we determine how this constrains the extrapolation of baryon and meson octet matrix elements and form factors. In particular we can construct certain combinations, which fan out from symmetric point (when all the quark masses are degenerate) to the point when the light and strange quarks take their...
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Daniel Jenkins (Universitรคt Regensburg)7/26/21, 1:30โฏPMHadron StructureOral presentation
We report on the recent progress of our analysis into nucleon sigma terms, as well as the singlet axial and tensor nucleon charges. These are extracted from the CLS gauge configurations, which utilise the Luฬscher-Weisz gluon action and the Sheikholeslami-Wohlert fermion action with $N_f = 2 + 1$ fermions, with pion masses ranging from the physical value up to 410 MeV, and lattice spacings...
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Konstantin Ottnad (University of Mainz)7/26/21, 1:45โฏPMHadron StructureOral presentation
Preliminary results are presented for nucleon isovector charges and twist-2 matrix elements which have been obtained employing an improved analysis strategy to deal with excited state contamination. The set of CLS N_f=2+1 gauge ensembles in this study has been extended compared to our 2018 calculation, including an ensemble at physical quark masses. Besides the addition of new ensembles, the...
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Sungwoo Park (Los Alamos National Laboratory)7/26/21, 2:00โฏPMHadron StructureOral presentation
We present updates on the calculation of flavor diagonal axial, tensor and scalar nucleon charges $g_{A,S,T}^{u,d,s}$ focusing on understanding the excited state contamination (ESC) including contributions of possible low-lying ($N\pi$ and $N\pi\pi$) excited states to individual nucleon matrix elements.
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Rajan Gupta (Los Alamos National Lab)7/26/21, 2:15โฏPMHadron StructureOral presentation
Starting with a summary of our studies of the sensitivity of various charges and form factors to the excited state spectrum, including input from PCAC, vector meson dominance and chiral perturbation theory, I will present an update on results for nucleon charges and form factors.
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Santanu Mondal7/26/21, 2:30โฏPMHadron StructureOral presentation
In this talk, I will discuss our recent calculations (Phys. Rev. D102 (2020) no.5, 054512, JHEP 2104 (2021) 044 ) of the first x-moment of nucleon isovector polarized, unpolarized and transversity distributions (momentum fraction, helicity and transversity moment respectively). We use the standard method for the calculation of these moments (via matrix elements of twist two operators), we...
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Andre Walker-Loud (Lawrence Berkeley National Laboratory)7/26/21, 2:45โฏPMHadron StructureOral presentation
We have implemented and are computing nucleon 3pt functions using the stochastic Laplacian Heaviside (sLapH) method. Such a technique enables the use of momentum space creation and annihilation operators providing access to the Breit-Frame as well as full control of the spin of the initial and final operator. It also enables the use of multi-hadron operators, for example the problematic N-pi...
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Ryutaro Tsuji7/26/21, 9:00โฏPMHadron StructureOral presentation
We will present the current status of nucleon structure studies with physical light quarks ($m_\pi$ = 135 MeV) in a large spatial extent of about 10 fm. Our calculations are carried out with the PACS10 gauge configurations generated by the PACS Collaboration with the stout-smeared O(a) improved Wilson fermions and Iwasaki gauge action at $\beta$=1.82 corresponding to the lattice spacing of...
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Dr Kadir Utku Can (The University of Adelaide)7/26/21, 9:15โฏPMHadron StructureOral presentation
We highlight QCDSF/UKQCD Collaboration's recent developments on computing the Compton amplitude directly via an implementation of the second-order Feynman-Hellmann theorem. As an application, we compute the nucleon Compton tensor across a range of photon momenta at an unphysical quark mass. This enables us to study the $Q^2$ dependence of the low moments of the nucleon structure functions in a...
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Mischa Batelaan (The University of Adelaide)7/26/21, 9:30โฏPMHadron StructureOral presentation
Lattice QCD calculations of the nucleon electromagnetic form factors are of interest at the high and low momentum transfer regions. For high momentum transfers especially there are open questions, such as the zero crossing in the proton's electric form factor, which require more calculations. We will present recent progress from the QCDSF/UKQCD/CSSM collaboration on the calculations of these...
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Mr Alec Hannaford-Gunn (The University of Adelaide)7/26/21, 9:45โฏPMHadron StructureOral presentation
We report on the use of Feynman-Hellmann techniques to calculate the off-forward Compton amplitude (OFCA) in lattice QCD. At leading-twist, the Euclidean OFCA is parameterised by moments of generalised parton distributions (GPDs). Hence this calculation provides the opportunity to determine GPD-related quantities from first principles.
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Yang Fu7/27/21, 5:00โฏAMHadron StructureOral presentation
The measurement of muonic-hydrogen spectroscopy provides the most precise determination of the proton charge radius, where the two-photon exchange contribution plays an important role in the understanding of $\mu$H spectroscopy. We will report a lattice QCD calculation of the two-photon exchange contribution by constructing the proton four-point correlation function.
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Shigemi Ohta (KEK High Energy Accelerator Organization)7/27/21, 5:15โฏAMHadron StructureOral presentation
Nucleon isovector form factors calculated on 2+1-flavor domain-wall fermion (DWF) numerical lattice-QCD ensemble with phyaical up-, down- and strange-quark mass and lattice momentum cut off of about 1.730(4) GeV will be reported.
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Xuan-He Wang7/27/21, 5:30โฏAMHadron StructureOral presentation
The electromagnetic polarizability is an important property of nucleon. It describes the response of a nucleon when it is placed in an external electric or magnetic field. The polarizability can be extracted from the real or virtual Compton scattering process $\gamma N \to \gamma N$. We develop a method to calculate the the Compton scattering matrix elements of nucleon from a 4-point...
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Simon Weishรคupl (Universitรคt Regensburg)7/27/21, 5:45โฏAMHadron StructureOral presentation
In the analysis of (lattice) QCD observables very often chiral perturbation theory (ChPT) is heavily used to describe the quark mass dependence or relate different observables via symmetry relations. Within ChPT the low energy constants (LECs) play a crucial role and their precise knowledge is important in lattice QCD as well as in phenomenology. While there are many lattice determinations of...
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Jonathan Lozano de la Parra (University of Bonn)7/27/21, 6:00โฏAMHadron StructureOral presentation
The study of the Compton amplitude has gained attention in recent years. It plays a central role in the analysis of many fundamental problems such as, for example, the evaluation of the Lamb shift in muonic hydrogen, or the calculation of the proton-neutron mass difference. Hence, the calculation of this amplitude on the lattice would definitely contribute to the solution of the above...
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Fabian Frech (Bergische Universitรคt Wuppertal)7/27/21, 6:15โฏAMHadron StructureOral presentation
We compute the quark-connected component of the hadronic vacuum polarization function at the energy scale of the Z boson mass in the Schwinger model. This is done by computing different representations of the Adler function on different energy scales. The mass parameters for the different scales are set with a step scaling scheme in which the lattice spacing and volume are adjusted to the...
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Nils Hermansson Truedsson (Universitรคt Bern)7/27/21, 6:30โฏAMHadron StructureOral presentation
In this talk we present a relativistic and model-independent method to analytically derive electromagnetic finite-size effects beyond the point-like approximation. Structure-dependence appears in terms of physical form-factors and derivatives thereof. The values of these physical quantities can be taken either from experimental measurements or auxiliary lattice calculations. We apply our...
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Dr Oliver Baer (Humboldt University Berlin, Germany)7/27/21, 6:45โฏAMHadron StructureOral presentation
The nucleon-pion-state contribution to QCD two-point and three-point functions relevant for lattice calculations of the nucleon electromagnetic form factors are studied in chiral perturbation theory.
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To leading order the results depend on a few experimentally known low-energy constants only, and the nucleon-pion-state contribution to the form factors can be estimated. The nucleon-pion-state... -
Mr Miguel Salg (University of Mainz)7/27/21, 7:00โฏAMHadron StructureOral presentation
We present results for the isoscalar electromagnetic form factors of the nucleon computed on the CLS ensembles with $N_\mathrm{f} = 2 + 1$ flavors of $\mathcal{O}(a)$-improved Wilson fermions and an $\mathcal{O}(a)$-improved conserved vector current. In order to estimate the excited-state contamination, we investigate several source-sink separations and apply the summation method. For the...
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Matthias F M Lutz (GSI)7/27/21, 7:15โฏAMHadron StructureOral presentation
We consider the chiral Lagrangian with nucleon, isobar, and pion degrees of freedom. The baryon masses and the axial-vector form factor of the nucleon are derived at the one-loop level. We explore the impact of using on-shell baryon masses in the loop expressions. As compared to results from conventional chiral perturbation theory we find significant differences. An application to QCD lattice...
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Giannis Koutsou (The Cyprus Institute)7/27/21, 7:30โฏAMHadron StructureOral presentation
We present the nucleon axial and electromagnetic form factors using $N_\textrm{f}=2+1+1$ twisted mass lattice QCD with clover improvement and with quarks with masses tuned to their physical values. Excited state effects are studied using several sink-source separations in the range 0.8 fm - 1.6 fm, exponentially increasing statistics with the separation such that statistical errors remain...
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Mr Tobias Schulz (Institute for Nuclear Physics, University of Mainz)7/27/21, 7:45โฏAMHadron StructureOral presentation
We present the analysis of isovector axial vector nucleon form factors for a set of $N_f=2+1$ CLS ensembles with $\mathcal O(a)$-improved Wilson fermions and Lรผscher-Weisz gauge action. The set of ensembles covers a pion mass range of $M_\pi=130-353\,$MeV with lattice spacings between $a=0.05-0.09\,$fm. In particular, the ensemble list includes a $96^{3}$ box ensemble at the physical pion...
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Daniel Simons (University of Iowa)7/27/21, 1:00โฏPMHadron StructureOral presentation
We studied the decay rate of the particle decay $B^0 \rightarrow D^- \ell^+ \nu_{\ell}$ using data collected from the Belle Collaboration. In order to analyze this decay rate, we used three parameterizations of the form factor which describes this process, the CLN (Caprini, Lellouch, and Neubert) parametrization, the BGL (Boyd, Grinstein, and Lebed) parametrization, and the BCL (Bourrely,...
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Yin Lin (University of Chicago)7/27/21, 1:15โฏPMHadron StructureOral presentation
In this talk, I will report our group's progress on calculating the nucleon axial form factor with the HISQ action for both valence and sea quarks. Nucleon matrix elements with staggered fermions require careful analysis of the staggered symmetry group. I will report a solution based on the generalized Wigner-Eckart theorem that enables us to extract physical observables from staggered...
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Aaron Meyer (University of California Berkeley)7/27/21, 1:30โฏPMHadron StructureOral presentation
The Deep Underground Neutrino Experiment (DUNE) is an upcoming neutrino oscillation experiment that is poised to answer key questions about the nature of the neutrino. Lattice QCD has the ability to make significant impact upon DUNE by computing the interaction of a nucleon to a weak current. Nucleon amplitudes involving the axial form factor are part of the primary signal measurement process...
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Dr Yong-Chull Jang (Columbia University)7/27/21, 1:45โฏPMHadron StructureOral presentation
The tension between the lattice calculation, the experimental data and the PCAC relation of the nucleon axial form factors - axial and (induced)-pseudoscalar - has been understood as a systematic resulting from missing multihadron (nucleon and pions) excited states in the analysis. These low-lying excited states are hard to resolve in the conventional analysis. Fits to the temporal component...
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Savvas Zafeiropoulos (Aix Marseille Univ. & CNRS)7/27/21, 2:00โฏPMHadron StructureOral presentation
The light-cone definition of Parton Distribution Functions (PDFs) does not allow for a direct ab initio determination employing methods of Lattice QCD simulations that naturally take place in Euclidean spacetime. In this presentation we focus on pseudo-PDFs where the starting point is the equal time hadronic matrix element with the quark and anti-quark fields separated by a finite distance. We...
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Kehfei Liu7/27/21, 2:15โฏPMHadron StructureOral presentation
Parton degrees of freedom (PDF) are classified in the Euclidean path-integral formulation of the hadronic tensor in QCD. They include the valence and connected sea partons, the connected sea antipartons, and the disconnected sea partons and antiprotons. These degrees of freedom are shown to be the same as those from the quasi-PDF, pseudo-PDF and lattice cross section approaches on the lattice....
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Floriano Manigrasso (University of Cyprus)7/27/21, 2:30โฏPMHadron StructureOral presentation
We present an ab initio calculation of the individual up, down, and strange quark unpolarized, helicity, and transversity parton distribution functions for the proton. The calculation is performed within the twisted mass clover-improved fermion formulation of lattice QCD. We use a $N_f = 2 + 1 + 1$ gauge ensemble simulated with pion mass $M_\pi = 250$ MeV, $M_\pi L \approx 3.8$ and lattice...
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Raza Sufian (William & Mary / Jefferson Lab)7/27/21, 2:45โฏPMHadron StructureOral presentation
We present a calculation of lattice QCD non-local matrix elements that can be used to determine polarized gluon Ioffe-time distribution and the corresponding parton distribution function using QCD short distance factorization. We construct the nucleon interpolation fields using the distillation technique and flow the gauge fields using the gradient flow. Our calculation is performed on a $32^3...
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Md Tanjib Atique Khan (Thomas Jefferson National Accelerator Facility)7/27/21, 9:00โฏPMHadron StructureOral presentation
We present our calculation of the unpolarized gluon parton distribution function (PDF) in the nucleon using the Pseudo-PDF technique on a $32^3 \times 64$ isotropic lattice with a pion mass of 358 MeV. The nucleon interpolating fields are reconstructed using distillation and we apply the sGEVP method to calculate the gluonic matrix elements. We smear the gauge fields using the gradient-flow to...
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Zhouyou Fan7/27/21, 9:15โฏPMHadron StructureOral presentation
We present the first determination of the $x$-dependent pion gluon distribution from lattice QCD using the pseudo-PDF approach, on lattice ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ), generated by MILC Collaboration. We use clover fermions for the valence action and momentum smearing to achieve pion boost momentum up to 2.29~GeV on two lattice spacings $a\approx...
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Wayne Morris (Old Dominion University)7/27/21, 9:30โฏPMHadron StructureOral presentation
We present the results that are necessary in the ongoing lattice calculations of the unpolarized and polarized gluon parton distribution functions (PDFs) within the pseudo-PDF approach. We give a classification of possible two-gluon correlator functions and identify those that contain the invariant amplitude determining the gluon PDF in the light-cone $z^2\to 0$ limit. One-loop calculations...
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Rui Zhang (Michigan state university)7/27/21, 9:45โฏPMHadron StructureOral presentation
We present preliminary lattice calculations of strange and charm contributions to nucleon charges and moments. The scalar charge, axial charge, tensor charge, and unpolarized first moments are calculated on five clover-on-HISQ lattices covering three lattice spacings $a=\{0.06,0.09,0.12\}$~fm and three pion masses $M_\pi=\{310,220,130\}$~MeV. We renormalize the matrix elements with...
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Daniel Hackett (MIT)7/27/21, 10:00โฏPMHadron StructureOral presentation
Hadronic matrix elements of the QCD energy-momentum tensor can be parametrized in terms of gravitational form factors (GFFs) which, through their dependence on momentum transfer and decomposition into quark and glue contributions, encode information about the distributions of energy, angular momentum, pressure, and shear forces within a hadron spatially and amongst its constituents. We report...
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Dimitra Pefkou (Massachusetts Institute of Technology)7/27/21, 10:15โฏPMHadron StructureOral presentation
The gravitational form factors (GFFs) of hadrons are the form factors of the energy momentum tensor of QCD, which quantifies how the energy, spin and mechanical properties are distributed within hadrons and how they split between the quark and gluon degrees of freedom. We use the Belifante-Rosenfeld prescription in a Lattice QCD calculation with pion mass $m_{\pi} = 450 \; \text{MeV}$ to...
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Fangcheng He (Institute of Theoretical Physics๏ผChinese Academy of Sciences)7/27/21, 10:30โฏPMHadron StructureOral presentation
We present the first Lattice QCD calculation of the quark and gluon trace anomaly contributions to the hadron masses, using the overlap fermion on the 2+1 flavor dynamical Domain wall quark ensemble. The result shows that the gluon trace anomaly contributes to most of the nucleon mass, and the contribution in the pion state is smaller than that in others.
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Yi-Bo Yang (CAS)7/27/21, 10:45โฏPMHadron StructureOral presentation
The momentum subtraction scheme (MOM) and symmetric momentum subtraction scheme (SMOM) are two of the widely used intermedium schemes for the non-perturbative renormalization of the lattice bare vertices. In principle both the schemes should provide the same MS-bar results with their respective matching, while kinds of the systematic uncertainties can create certain tensions especially at...
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Marius Lรถffler (Regensburg University)7/28/21, 5:00โฏAMHadron StructureOral presentation
The rho meson is the lightest strongly decaying particle and also the simplest spin-1 meson, which allows for the study of polarisation dependent structure functions that are not present in the spin-1/2 case. Its unstable nature complicates the analysis of its structure, both on the lattice and in experiment. However, it allows us to study the interplay between hadron polarization and parton...
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Christian Zimmermann (University of Regensburg)7/28/21, 5:15โฏAMHadron StructureOral presentation
We provide a first study of Mellin moments of double parton distributions (DPDs) in the nucleon on the lattice, where we consider several combinations of quark flavors and polarizations. These are accessible through two-current correlations, which can be obtained by evaluating four-point functions. In this context we consider all possible Wick contractions, where for almost all of them...
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Filippo Mazzetti (Universitร degli studi Roma Tre)7/28/21, 5:30โฏAMHadron StructureOral presentation
We study, with lattice QCD, the leptonic decays of pseudoscalar mesons of the type $P^+\to l^+\,\nu_l\,l'^+\,l'^-$. These processes are mediated by the emission of a virtual photon which also interacts with the hadronic structure of the pseudoscalar meson $P^+$, giving rise to relevant structure-dependent corrections. They are very suppressed processes, which thus provide an excellent test for...
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Dr Gregoris Spanoudes (University of Cyprus)7/28/21, 5:45โฏAMHadron StructureOral presentation
We study a gauge-invariant renormalization scheme (GIRS) for composite operators, regularized on the lattice, by extending the coordinate space (X-space) scheme proposed some years ago. In this scheme, Green's functions of products of gauge-invariant operators located at different spacetime points are considered. Due to the gauge-invariant nature of GIRS, gauge fixing is not needed in the...
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Colin Egerer (William and Mary)7/28/21, 6:00โฏAMHadron StructureOral presentation
The pseudo-distribution formalism is one such methodology capable of illuminating the collinear structure of hadrons from matrix elements of suitably constructed space-like operators calculated using lattice QCD. Looking more closely at the unpolarized nucleon PDF calculation of the HadStruc collaboration, the improved statistical quality of the computed Ioffe-time pseudo-distributions opens...
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Jianhui Zhang (Beijing Normal University)7/28/21, 6:15โฏAMHadron StructureOral presentation
Calculating the partonic structure of hadrons from lattice QCD has attracted a lot of interest in the past few years, and now has moved to a stage which calls for precision. In this talk, I'll discuss some important steps towards such precision calculations.
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Ruilin Zhu (Nanjing Normal University)7/28/21, 6:30โฏAMHadron StructureOral presentation
We present the next-to-next-to-leading order (NNLO) calculation of quark quasiparton distribution functions (PDFs) in the large momentum effective theory. The nontrivial factorization at this order is established explicitly and the full analytic matching coefficients between the quasidistribution and the light-cone distribution are derived. In the end we get the PDFs within our NNLO matching...
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Shicheng Xia (Peking University)7/28/21, 6:45โฏAMHadron StructureOral presentation
The transverse momentum dependent soft function introduced to describe soft-gluon effects plays an important role in QCD factorization. We present a lattice QCD study on this function by simulating pion matrix element and quasi TMD wave function using the large momentum effective theory. The momenta we adopted are up to $3 $ GeV. Various systematic effects are examined in our study.
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Maximilian Schlemmer (University of Regensburg)7/28/21, 7:00โฏAMHadron StructureOral presentation
We present lattice results for the non-perturbative Collins-Soper (CS) kernel, which describes the energy-dependence of transverse momentum-dependent parton distributions (TMDs). The CS kernel is extracted from the ratios of first Mellin moments of quasi-TMDs evaluated at different nucleon momenta.The analysis is done with dynamical $N_f=2+1$ clover fermions for the CLS ensemble H101...
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Mr -Yizhuang -Liu (jagiellonian university)7/28/21, 7:15โฏAMHadron StructureOral presentation
We show that the transverse momentum dependent parton distribution functions
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(TMDPDFs), important for understanding 3D hadron structure and describing
high-energy experiments, can be formulated in the framework of the
large-momentum effective theory(LaMET). We show that the quasi-TMDPDFs,
calculable on lattice, factorize at large momentum limit into physical-TMDPDFs
and reduced soft... -
Qi-An Zhang (Shanghai Jiao Tong University)7/28/21, 7:30โฏAMHadron StructureOral presentation
The transverse-momentum-dependent (TMD) soft function is a key ingredient in QCD factorization of Drell-Yan and other processes with relatively small transverse momentum. We present a lattice QCD study of this function at moderately large rapidity on a 2+1 ๏ฌavor CLS dynamic ensemble with a = 0.098 fm. We extract the rapidity-independent (or intrinsic) part of the soft function through a...
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Min-Huan Chu (Shanghai Jiao Tong University)7/28/21, 7:45โฏAMHadron StructureOral presentation
Weโll present the first lattice QCD calculation of transverse momentum dependence wave function of pion using large momentum effective theory. We use the clover fermion action on three ensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ) action, generated by MILC collaboration, at pion mass $670MeV$ and $0.12 fm$ lattice spacing, choose three different hadron momenta...
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Dr Yong Zhao (Argonne National Laboratory)7/28/21, 2:00โฏPMHadron StructureOral presentation
In this talk, we present a model-independent calculation of the $x$-dependence of pion valence PDF with the large-momentum effective theory approach. In this calculation we adopt the most up-to-date theoretical developments on the systematic corrections, which include the hybrid renormalization scheme that rigorously renormalizes the lattice matrix elements at both short and long distances, as...
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Xiang Gao (Tsinghua University)7/28/21, 2:15โฏPMHadron StructureOral presentation
We study pion valence structure from lattice QCD using three mixed action ensambles including a physical pion mass with fine lattice spacings of a = 0.04, 0.06 and 0.076 fm. Our analysis use ratio-based scheme and hybrid scheme to renormalize the equal-time bilocal quark-bilinear matrix elements. We extract first few moments and reconstruct the x-dependent PDF using NNLO leading-twist...
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Dr Nikhil Karthik (Jefferson Lab and William & Mary), Nikhil Karthik (Thomas Jefferson National Accelerator Facility)7/28/21, 2:30โฏPMHadron StructureOral presentation
The transversity parton distribution function probes the x-dependent difference between quarks with their spins aligned and anti-aligned with the transverse polarization of the nucleon. The chiral-odd nature of the transversity makes it experimentally harder to extract than unpolarized distributions, thereby making the lattice determination crucial. In this talk, we will present results on...
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Huey-Wen Lin7/28/21, 2:45โฏPMHadron StructureOral presentation
The largeโmomentum effective theory (LaMET) framework has been widely used to determine the Bjorkenโx dependence of PDFs in latticeโQCD hadron-structure calculations. In this talk, I will highlight selected recent lattice-QCD results on parton distributions from MSULat.
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*This work is supported by the US National Science Foundation under grant PHY 1653405 โCAREER: Constraining Parton... -
Colin Lauer (Temple University)7/28/21, 9:00โฏPMHadron StructureOral presentation
We present a calculation of the connected-diagram contributions to the
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first three non-trivial Mellin moments for the pion and kaon extracted
directly in lattice QCD using local operators with up to 3 covariant
derivatives. We reconstruct the $x$-dependence of the pion and kaon
PDFs via fits to our results. We find that the reconstruction is
feasible and that our lattice data favor a... -
Prof. Stefan Meinel (University of Arizona)7/28/21, 9:15โฏPMHadron StructureOral presentation
The hadronic physics of the simplest semileptonic decays of $\Lambda_b$'s and $\Lambda_c$'s, in which both the initial and final baryons have $J^P=\frac12^+$, is by now quite well understood. We have begun exploring more complicated processes with $J^P=\frac12^-$ and $J^P=\frac32^-$ baryons in the final state, which have a rich phenomenology but are more challenging for theory and experiment....
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Yushan Su (University of Maryland)7/28/21, 9:30โฏPMHadron StructureOral presentation
Large-momentum effective theory provides a way to extract the parton physics from lattice data based on first-principle calculation. In applying large-momentum effective theory, renormalization of
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the Euclidean correlators in lattice regularization is a challenge due to
linear divergences in the self-energy of Wilson lines.
Based on lattice QCD matrix elements of the quasi-PDF operator at... -
Shoji Hashimoto (KEK)7/28/21, 9:45โฏPMHadron StructureOral presentation
Utilizing the approach recently proposed for the inclusive semi-leptonic decay rate on the lattice, we compute the differential decay rate of a B_s meson for various kinematical channels. The results are compared with the contributions from the ground states (D and D) as well as from the orbitally excited states (D*'s). The computation so far is carried out with an unphysically light bottom...
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Jun-Sik Yoo (KEK, Japan)7/28/21, 10:00โฏPMHadron StructureOral presentation
We compute the inclusive neutrino-nucleon scattering cross sections from
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the first principles of QCD. This is highly relevant to the recent and
future $\nu-N$ scattering experiments , whose energy regime is excessively low
for the perturbative analysis to hold. We use a technique recently
proposed
to treat the inclusive contributions on the lattice. We compute the
forward... -
Noriyoshi Ishii (Osaka University)7/28/21, 10:15โฏPMHadron StructureOral presentation
In Phys.Rev.Lett.107,091601, T.Kawanai and S.Sasaki extended HAL QCD method to the ccbar system and showed numerically that the qqbar potential obtained from the Nambu-Bethe-Salpeter wave function agrees with the qqbar potential obtained from Wilson loop in the heavy quark mass limit. However, it is not known how these two potentials can agree. In this talk, the relation between these two...
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Eddie Sankey (University of Adelaide)7/28/21, 10:30โฏPMHadron StructureOral presentation
The nucleon forward Compton amplitude describes the process of a virtual photon scattering on a nucleon. It is an important object which encodes insights into hadronic structure. The real part of this amplitude contains a component that is unconstrained by a dispersive representation in terms of inelastic scattering data. This component, commonly referred to as the `subtraction function',...
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Kyriakos Hadjiyiannakou (The Cyprus Institute)7/29/21, 1:00โฏPMHadron StructureOral presentation
The origin of the proton spin has attracted a lot of attention since the first surprising result from the European Muon Collaboration about 30 years ago. We present a significant step towards solving the proton spin puzzle. The calculation is done using $N_f=2+1+1$ twisted mass fermions directly at the physical point. Both gluon and quark contributions to the proton spin are evaluated, where...
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Luigi Del Debbio (The University of Edinburgh (GB))7/29/21, 1:15โฏPMHadron StructureOral presentation
We review recent theoretical developments concerning the definition and the renormalization of equal-time correlators that can be computed on the lattice and related to Parton Distribution Functions (PDFs) through a factorization formula. We focus on the theoretical aspects in the context of a scalar field theory.
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Aurora Scapellato (Temple University)7/29/21, 1:30โฏPMHadron StructureOral presentation
Generalized parton distributions (GPDs) are among the most fundamental quantities for describing the internal structure of hadrons, providing information about the momentum and spatial distributions of quarks and gluons. Exclusive scattering processes offer a natural framework to extract GPDs from experiments. However, the exclusivity of the process and their indirect relation to the...
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Andreas Metz (Temple University)7/29/21, 1:45โฏPMHadron StructureOral presentation
During recent years there has been a tremendous and exciting activity which aims at calculating the full x-dependence of parton distributions (PDFs) and related quantities in lattice QCD. To this end one needs to compute Euclidean correlators which through a perturbative matching procedure can be related to the light-cone correlation functions of interest. While the matching has already been...
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Prof. Martha Constantinou (Temple University)7/29/21, 2:00โฏPMHadron StructureOral presentation
The non-perturbative part of the cross-section of high-energy processes may be expanded in terms of the process's large energy scale. This gives rise to a tower of distribution functions, labeled by their twist (mass dimension minus spin). The leading twist (twist-2) contributions have been at the center of experimental measurements, theoretical investigations, and lattice QCD calculations. It...
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Dr Ryan Bignell (Swansea University)7/29/21, 2:15โฏPMHadron StructureOral presentation
The magnetic polarisability of the pion is calculated at a range of quark masses using the background field method. These results are facilitated by the use of the background-field corrected clover fermion action which removes the unphysical quark mass renormalisation due to the Wilson term in a background magnetic field. A magnetic-field dependent quark-propagator projector enables the ground...
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Hossein Niyazi (The George Washington University)7/29/21, 2:30โฏPMHadron StructureOral presentation
Electric and magnetic polarizabilities are two of the fundamental properties of hadrons which help us understand the distribution of charge and currents inside hadrons and how they respond to external electromagnetic fields. For nucleons, these values are determined experimentally from Compton scattering. For charged pions, the experiments are more challenging since no free pion target is...
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Luchang Jin7/29/21, 2:45โฏPMHadron StructureOral presentation
We report a first principle lattice calculation of the pion electric polarizablity $\alpha_\pi$. First, we derive the master formula, which relate the pion polarizabilies with the position space hadronic Compton tensor, $\langle \pi | J_\mu(x) J_\nu(0) | \pi \rangle$. Then, the hadronic tensor is calculated using Domain Wall fermions directly at physical pion mass. The gauge ensembles are...
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Anthony Grebe (Massachusetts Institute of Technology)7/29/21, 9:00โฏPMHadron StructureOral presentation
The light-cone distribution amplitude (LCDA) of the pion carries information about the distribution of its quarks, which is an important input to various experiments. We present our proof-of-concept lattice calculation of the second Mellin moment of the LCDA using the heavy quark operator product expansion (HOPE) method. Our computation shows agreement with complementary methods of...
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Robert Perry7/29/21, 9:15โฏPMHadron StructureOral presentation
The light-cone distribution amplitude (LCDA) is a key object of interest in a range of high-energy, exclusive processes in QCD. In this talk, we describe the application of the heavy quark operator product expansion (HOPE) method to a preliminary study of the fourth Mellin moment of the pion LCDA. We present an exploratory investigation at a pion mass of 560 MeV in the quenched approximation.
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Jun Hua (Shanghai Jiao Tong University)7/29/21, 9:30โฏPMHadron StructureOral presentation
We present the first lattice QCD calculation of the distribution amplitudes of longitudinally and transversely polarized vector mesons Kโ and ฯ using large momentum effective theory. We use the clover fermion action on three ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ) action, generated by MILC collaboration, at physical pion mass and {0.06, 0.09, 0.12} fm lattice...
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Philipp Scior (Universitรคt Bielefeld)7/29/21, 9:45โฏPMHadron StructureOral presentation
We will present lattice QCD results for x-dependent distribution amplitudes for pion and kaon. The computations were carried out using valence Wilson Clover fermions on HISQ gauge configurations with 2+1 flavors, all with physical values of pion and kaon masses and at a lattice spacing of 0.076 fm. Computations used hadrons states boosted up to a momentum of 1.7 GeV. To arrive at the results...
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Nicholas Juliano7/29/21, 10:00โฏPMHadron StructureOral presentation
We present a lattice-QCD calculation of the pion distribution amplitudes using large-momentum effective theory (LaMET). Our calculation is carried out using three ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ), generated by MILC collaboration, at 310 MeV pion mass with 0.06, 0.09, 0.12 and 0.15 fm lattice spacings. We use clover fermion action for the valence quarks...
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Michael Engelhardt7/29/21, 10:15โฏPMHadron StructureOral presentation
Generalized transverse momentum-dependent parton distributions (GTMDs) provide a comprehensive framework for imaging the internal structure of the proton. In particular, by encoding the simultaneous distribution of quark transverse positions and momenta, they allow one to directly access longitudinal quark orbital angular momentum, and, moreover, to correlate it with the quark helicity. The...
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Gen Wang (University of Kentucky)7/29/21, 10:30โฏPMHadron StructureOral presentation
We present a calculation of the proton momentum and angular momentum decomposition using overlap fermions on a 2+1-flavor RBC/UKQCD domain-wall configuration at around 171 MeV which is close to the physical pion mass. A complete determination of the momentum and angular momentum fractions carried by up, down, strange and glue inside proton has been done with valence pion masses varying from...
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Tomas Howson7/29/21, 10:45โฏPMHadron StructureOral presentation
With upcoming Electron-Ion Colliders, such as the eRHIC at Brookhaven National Laboratory and a proposed upgrade to the LHC, the structure of the hadron from both the quark and gluon sectors is quickly becoming a readily accessible frontier in physical investigation. Such experiments are underpinned by a strong theoretical foundation, such as that provided by lattice QCD.
We will show...
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