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We present a new method, based on Gaussian process regression, for reconstructing the continuous $x$-dependence of parton distribution functions (PDFs) from quasi-PDFs computed using lattice QCD. We examine the origin of the unphysical…

High Energy Physics - Lattice · Physics 2020-11-25 Constantia Alexandrou , Giovanni Iannelli , Karl Jansen , Floriano Manigrasso

Parton distribution functions (PDFs) are nonperturbative objects defined by nonlocal light-cone correlations. They cannot be computed directly from Quantum Chromodynamics (QCD). Using a standard lattice QCD approach, it is possible to…

High Energy Physics - Phenomenology · Physics 2017-02-08 Alessandro Bacchetta , Marco Radici , Barbara Pasquini , Xiaonu Xiong

We propose a new method to calculate parton distribution functions (PDFs) from lattice correlations of boosted quarks and gluons in the Coulomb gauge. Compared to the widely used gauge-invariant Wilson-line operators, these correlations…

High Energy Physics - Phenomenology · Physics 2024-04-30 Xiang Gao , Wei-Yang Liu , Yong Zhao

We present lattice results for the isovector unpolarized parton distribution with nonperturbative RI/MOM-scheme renormalization on the lattice. In the framework of large-momentum effective field theory (LaMET), the full Bjorken-$x$…

High Energy Physics - Lattice · Physics 2018-01-24 Jiunn-Wei Chen , Tomomi Ishikawa , Luchang Jin , Huey-Wen Lin , Yi-Bo Yang , Jian-Hui Zhang , Yong Zhao

We present a detailed study of the helicity-dependent and helicity-independent collinear parton distribution functions (PDFs) of the nucleon, using the quasi-PDF approach. The lattice QCD computation is performed employing twisted mass…

We present a lattice quantum chromodynamics calculation of the $x$-dependent isovector quark helicity parton distribution function (PDF) of the proton in the large momentum effective theory (LaMET) framework. Through operator product…

High Energy Physics - Lattice · Physics 2026-04-06 Xiang Gao , Andrew D. Hanlon , Swagato Mukherjee , Peter Petreczky , Hai-Tao Shu , Fei Yao , Rui Zhang , Yong Zhao

In this document, we summarize the status and challenges of calculating parton physics in lattice QCD for the US Particle Physics Community Planning Exercise (a.k.a. "Snowmass"). While PDF-moments calculations have been very successful and…

We report a lattice QCD calculation of the parton distribution function (PDF) of a deuteron-like dibaryon system using large-momentum effective theory. The calculation is done on three Wilson Clover ensembles with a fixed lattice spacing…

High Energy Physics - Lattice · Physics 2025-05-20 Chen Chen , Liuming Liu , Peng Sun , Yi-Bo Yang , Yiqi Geng , Fei Yao , Jian-Hui Zhang , Kuan Zhang

We present results for the flavor non-singlet u-d parton distribution functions within the nucleon using the quasi-PDF approach. The lattice calculation is performed by employing the twisted mass formulation and two gauge ensembles, having…

Recently, a novel approach has been proposed to compute parton distributions through the use of boosted correlators fixed in the Coulomb gauge from lattice QCD, within the framework of Large-Momentum Effective Theory (LaMET). This approach…

High Energy Physics - Lattice · Physics 2026-02-13 Xiang Gao , Jinchen He , Joshua Lin , Swagato Mukherjee , Peter Petreczky , Rui Zhang , Yong Zhao

A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when…

High Energy Physics - Phenomenology · Physics 2015-03-03 Leonard Gamberg , Zhong-Bo Kang , Ivan Vitev , Hongxi Xing

Gluon parton distribution functions (PDFs) in the proton can be calculated directly on Euclidean lattices using large momentum effective theory (LaMET). To realize this goal, one has to find renormalized gluon quasi-PDFs in which power…

High Energy Physics - Phenomenology · Physics 2019-04-11 Jian-Hui Zhang , Xiangdong Ji , Andreas Schäfer , Wei Wang , Shuai Zhao

We present a state-of-the-art calculation of the isovector quark helicity Bjorken-$x$ distribution in the proton using lattice-QCD ensembles at the physical pion mass. We compute quasi-distributions at proton momenta $P_z \in \{2.2, 2.6,…

High Energy Physics - Lattice · Physics 2019-01-29 Huey-Wen Lin , Jiunn-Wei Chen , Xiangdong Ji , Luchang Jin , Ruizi Li , Yu-Sheng Liu , Yi-Bo Yang , Jian-Hui Zhang , Yong Zhao

We show the first results for parton distribution functions within the proton at the physical pion mass, employing the method of quasi-distributions. In particular, we present the matrix elements for the iso-vector combination of the…

In this work, we present a first-principles lattice-QCD calculation of the unpolarized quark PDF for the pion and the kaon. The lattice data rely on matrix elements calculated for boosted mesons coupled to non-local operators containing a…

High Energy Physics - Lattice · Physics 2026-05-20 Joshua Miller , Joseph Torsiello , Isaac Anderson , Krzysztof Cichy , Martha Constantinou , Joseph Delmar , Sarah Lampreich

We present a lattice QCD calculation of the unpolarized isovector quark parton distribution function (PDF) of the proton utilizing a perturbative matching at next-to-next-to-leading-order (NNLO). The calculations are carried out using a…

High Energy Physics - Lattice · Physics 2023-05-10 Xiang Gao , Andrew D. Hanlon , Jack Holligan , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Sergey Syritsyn , Yong Zhao

We present the first lattice calculation of the nucleon isovector unpolarized generalized parton distribution (GPD) at the physical pion mass using a lattice ensemble with 2+1+1 flavors of highly improved staggered quarks (HISQ) generated…

High Energy Physics - Phenomenology · Physics 2021-11-10 Huey-Wen Lin

We present results for the unpolarized parton distribution function of the nucleon computed in lattice QCD at the physical pion mass. This is the first study of its kind employing the method of Ioffe time pseudo-distributions. Beyond the…

High Energy Physics - Lattice · Physics 2020-12-30 Bálint Joó , Joseph Karpie , Kostas Orginos , Anatoly V. Radyushkin , David G. Richards , Savvas Zafeiropoulos

We present a calculation of the bare quasi-PDF (qPDF) of the pion. We perform these calculations using the HotQCD HISQ gauge ensemble for our sea quarks along with a Wilson-Clover valence quark action. Our lattice size is $48^3\times64$,…

We present lattice QCD calculations of valence parton distribution function (PDF) of pion employing next-to-next-leading-order (NNLO) perturbative QCD matching. Our calculations are based on three gauge ensembles of 2+1 flavor highly…