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We present a lattice QCD determination of the Mellin moments of the unpolarized gluon parton distribution function in the proton. The analysis is based on matrix elements of nonlocal gluon operators coupled to momentum-boosted proton…

High Energy Physics - Lattice · Physics 2026-05-29 Joseph Delmar , Krzysztof Cichy , Martha Constantinou , Yong Zhao

The quasi parton distribution is a spatial correlation of quarks or gluons along the $z$ direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative…

High Energy Physics - Phenomenology · Physics 2018-03-28 Iain W. Stewart , Yong Zhao

We present a first machine learning-based decoding of the gluonic structure of the proton from lattice QCD using a variational autoencoder inverse mapper (VAIM). Harnessing the power of generative AI, we predict the parton distribution…

High Energy Physics - Phenomenology · Physics 2025-07-25 Brandon Kriesten , Alex NieMiera , William Good , T. J. Hobbs , Huey-Wen Lin

We identify the matrix elements necessary to determine the leading-twist gluon generalized parton distributions (GPDs) $H_g,~E_g,~\wt{H}_g,~\wt{E}_g,~H^T_g,~E^T_g, \wt{H}^T_g ,~\wt{E}^T_g$ in lattice QCD calculations. We present a method to…

High Energy Physics - Lattice · Physics 2025-05-16 Jakob Schoenleber , Raza Sabbir Sufian , Taku Izubuchi , Yi-Bo Yang

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…

We perform the first simultaneous global QCD analysis of pion and kaon parton distribution functions (PDFs), constrained by pion- and kaon-induced Drell-Yan (DY) and leading neutron electroproduction data, together with lattice QCD data on…

High Energy Physics - Phenomenology · Physics 2025-10-15 P. C. Barry , Chueng-Ryong Ji , W. Melnitchouk , N. Sato , Fernanda Steffens

We study isovector unpolarized and helicity parton distribution functions (PDF) of the proton within the framework of Large Momentum Effective Theory. We use a gauge ensemble, generated by the MILC Collaboration, with a superfine lattice…

High Energy Physics - Lattice · Physics 2020-10-19 Zhouyou Fan , Xiang Gao , Ruizi Li , Huey-Wen Lin , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Sergey Syritsyn , Yi-Bo Yang , Rui Zhang

We study the factorization relations between quasi gluon GPDs and twist-2 GPDs. The perturbative coefficient functions are obtained at one-loop level. They are free from any collinear- or I.R. divergences. Unlike the case of the…

High Energy Physics - Phenomenology · Physics 2023-04-20 J. P. Ma , Z. Y. Pang , C. P. Zhang , G. P. Zhang

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

Even since the "quasi" parton distribution function (PDF) was proposed under the large-momentum effective theory (LaMET) framework, its renormalization under the lattice regularization has been a central challenge to be solved due to the…

High Energy Physics - Lattice · Physics 2019-12-17 Yikai Huo , Peng Sun

We present the results that are necessary in the ongoing lattice calculations of the gluon parton distribution functions (PDFs) within the pseudo-PDF approach. We identify the two-gluon correlator functions that contain the invariant…

High Energy Physics - Phenomenology · Physics 2021-07-20 I. Balitsky , W. Morris , A. Radyushkin

The NNPDF collaboration has recently presented NNPDF3.1, a new determination of the parton distribution functions (PDFs) of the proton including a number of new data, some of which are particularly sensitive to the gluon PDF at large x. In…

High Energy Physics - Phenomenology · Physics 2019-02-25 Emanuele R. Nocera , Maria Ubiali

In this work we present, for the first time, the non-perturbative renormalization for the unpolarized, helicity and transversity quasi-PDFs, in an RI' scheme. The proposed prescription addresses simultaneously all aspects of…

Within the framework of large momentum effective theory (LaMET), genenaralized parton distributions (GPDs) can be extracted from lattice calculations of quasi-GPDs through a perturbative matching relation, up to power corrections that are…

High Energy Physics - Phenomenology · Physics 2019-08-14 Yu-Sheng Liu , Wei Wang , Ji Xu , Qi-An Zhang , Jian-Hui Zhang , Shuai Zhao , Yong Zhao

We revise the relation between Parton Distribution Functions (PDFs) and matrix elements computable from lattice QCD, focusing on the quasi-Parton Distribution Functions (qPDFs) approach. We exploit the relation between PDFs and qPDFs in the…

High Energy Physics - Phenomenology · Physics 2020-01-08 Krzysztof Cichy , Luigi Del Debbio , Tommaso Giani

We present the first calculation of the pion gluon moment from lattice QCD in the continuum-physical limit. The calculation is done using clover fermions for the valence action with three pion masses, 220, 310 and 690 MeV, and three lattice…

High Energy Physics - Lattice · Physics 2023-10-19 William Good , Kinza Hasan , Allison Chevis , Huey-Wen Lin

We present the first lattice calculation of the nucleon isovector helicity parton distribution function (PDF) in the framework of large-momentum effective theory (LaMET) that uses the hybrid scheme with self-renormalization. We use…

High Energy Physics - Lattice · Physics 2024-05-29 Jack Holligan , Huey-Wen Lin

We present a next-to-next-to-leading order (NNLO) calculation of the quasi parton distribution functions (Quasi-PDFs) in the large momentum effective theory (LaMET). We focus on the flavor non-diagonal quark-quark channel and demonstrate…

High Energy Physics - Phenomenology · Physics 2020-08-05 Long-Bin Chen , Wei Wang , Ruilin Zhu

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

The quasi-PDF approach provides a path to computing parton distribution functions (PDFs) using lattice QCD. This approach requires matrix elements of a power-divergent operator in a nucleon at high momentum and one generically expects…