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We discuss strategies for comparisons of nonperturbative QCD predictions for parton distribution functions (PDFs) with high-energy experiments in the region of large partonic momentum fractions $x$. Analytic functional forms for PDFs cannot…

High Energy Physics - Phenomenology · Physics 2021-03-31 A. Courtoy , Pavel M. Nadolsky

We propose an efficacious approach to derive the generalized parton distributions for the pion and proton, based upon prior knowledge of their respective parton distribution functions (PDFs). Our method leverages on integral representations…

High Energy Physics - Phenomenology · Physics 2024-06-17 Xiaobin Wang , Zanbin Xing , Minghui Ding , Khépani Raya , Lei Chang

In this paper, we present lattice QCD results for the $x$-dependence of the unpolarized gluon PDF for the proton. We use one ensemble of $N_f=2+1+1$ maximally twisted mass fermions with a clover improvement, and the Iwasaki improved gluon…

High Energy Physics - Lattice · Physics 2023-10-03 Joseph Delmar , Constantia Alexandrou , Krzysztof Cichy , Martha Constantinou , Kyriakos Hadjiyiannakou

We present PDFFlow, a new software for fast evaluation of parton distribution functions (PDFs) designed for platforms with hardware accelerators. PDFs are essential for the calculation of particle physics observables through Monte Carlo…

High Energy Physics - Phenomenology · Physics 2021-05-19 Stefano Carrazza , Juan M. Cruz-Martinez , Marco Rossi

We present progress towards the first unpolarized gluon quasi-PDF from lattice QCD using high-statistics measurement with $a \approx 0.12$ fm and two valence pion masses $M_\pi \approx 310$ and $690$ MeV generated on $2+1+1$-flavors of HISQ…

High Energy Physics - Lattice · Physics 2024-09-05 William Good , Kinza Hasan , Huey-Wen Lin

Parton distribution function (PDF) at small $x$ in a fast-moving proton is investigated within an upgraded parton model that includes parton splitting with branching cascades and parton fusion. In the region of moderately small $x$, we…

High Energy Physics - Phenomenology · Physics 2026-02-27 M. L. Nekrasov

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 give a classification of possible two-gluon correlator functions and identify…

High Energy Physics - Phenomenology · Physics 2021-07-21 Ian Balitsky , Wayne Morris , Anatoly Radyushkin

We present the first exploratory lattice QCD calculation of the pion valence quark distribution extracted from spatially separated current-current correlations in coordinate space. We show that an antisymmetric combination of vector and…

High Energy Physics - Lattice · Physics 2019-04-17 Raza Sabbir Sufian , Joseph Karpie , Colin Egerer , Kostas Orginos , Jian-Wei Qiu , David G. Richards

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 present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with parton-parton recombination corrections and the…

High Energy Physics - Phenomenology · Physics 2021-06-03 Chengdong Han , Gang Xie , Rong Wang , Xurong Chen

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 review the present status of the determination of parton distribution functions (PDFs) in the light of the precision requirements for the LHC in Run 2 and other future hadron colliders. We provide brief reviews of all currently available…

High Energy Physics - Phenomenology · Physics 2016-09-21 A. Accardi , S. Alekhin , J. Blümlein , M. V. Garzelli , K. Lipka , W. Melnitchouk , S. Moch , R. Placakyte , J. F. Owens , E. Reya , N. Sato , A. Vogt , O. Zenaiev

We investigate the behavior of spin-dependent parton distribution functions (PDFs) at large parton momentum fractions x in the context of global QCD analysis. We explore the constraints from existing deep-inelastic scattering data, and from…

High Energy Physics - Phenomenology · Physics 2015-06-19 P. Jimenez-Delgado , H. Avakian , W. Melnitchouk

In this work, we report a lattice calculation of $x$-dependent valence pion generalized parton distributions (GPDs) at zero skewness with multiple values of the momentum transfer $-t$. The calculations are based on an $N_f=2+1$ gauge…

High Energy Physics - Lattice · Physics 2025-02-14 Heng-Tong Ding , Xiang Gao , Swagato Mukherjee , Peter Petreczky , Qi Shi , Sergey Syritsyn , Yong Zhao

We present the first unbiased determination of spin-dependent, or polarized, Parton Distribution Functions (PDFs) of the proton. A statistically sound representation of the corresponding uncertainties is achieved by means of the NNPDF…

High Energy Physics - Phenomenology · Physics 2014-03-04 Emanuele Roberto Nocera

We exploit a method introduced recently to determine parton distribution amplitudes (PDAs) from minimal information in order to obtain light-quark pseudoscalar and vector meson PDAs from the limited number of moments produced by numerical…

The parton distribution functions (PDFs) of heavy mesons are evaluated from their light-front wave functions, which are obtained from a basis light-front quantization in the leading Fock sector representation. We consider the mass…

Nuclear Theory · Physics 2020-07-22 Jiangshan Lan , Chandan Mondal , Meijian Li , Yang Li , Shuo Tang , Xingbo Zhao , James P. Vary

At large values of $x$ the parton distribution functions (PDFs) of the proton are poorly constrained and there are considerable variations between different global fits. Data at such high $x$ have already been published by the ZEUS…

High Energy Physics - Experiment · Physics 2021-07-14 Ritu Aggarwal

We present the first global analysis of generalized parton distributions (GPDs) combing lattice quantum chromodynamics (QCD) calculations and experiment measurements including global parton distribution functions (PDFs), form factors (FFs)…

High Energy Physics - Phenomenology · Physics 2023-06-13 Yuxun Guo , Xiangdong Ji , M. Gabriel Santiago , Kyle Shiells , Jinghong Yang

We present the next-to-next-to-leading order (NNLO) calculation of quark quasi parton distribution functions (PDFs) in the large momentum effective theory. The nontrivial factorization at this order is established explicitly and the full…

High Energy Physics - Phenomenology · Physics 2021-02-24 Long-Bin Chen , Wei Wang , Ruilin Zhu