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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

We present the first lattice QCD determination of the light cone gluon helicity correlation parton distribution function (PDF) with numerical evidence toward disfavoring negative gluon polarization in the nucleon. We present a solution for…

High Energy Physics - Lattice · Physics 2023-10-10 Tanjib Khan , Tianbo Liu , Raza Sabbir Sufian

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 present a determination of the parton distributions of the nucleon from a global set of hard scattering data using the NNPDF methodology: NNPDF2.0. Experimental data include deep-inelastic scattering with the combined HERA-I dataset,…

High Energy Physics - Phenomenology · Physics 2014-11-20 Richard D. Ball , Luigi Del Debbio , Stefano Forte , Alberto Guffanti , Jose I. Latorre , Juan Rojo , Maria Ubiali

To calculate the transverse-momentum-dependent parton distribution functions (TMDPDFs) from lattice QCD, an important goal yet to be realized, it is crucial to establish a viable non-perturbative renormalization approach for linear…

High Energy Physics - Lattice · Physics 2022-08-31 Kuan Zhang , Xiangdong Ji , Yi-Bo Yang , Fei Yao , Jian-Hui Zhang

We present new sets of nuclear parton distribution functions (nPDFs) at next-to-leading order and next-to-next-to-leading order in perturbative QCD. Our analyses are based on deeply inelastic scattering data with charged-lepton and neutrino…

High Energy Physics - Phenomenology · Physics 2022-06-09 Ilkka Helenius , Marina Walt , Werner Vogelsang

We present the first unbiased determination of parton distribution functions (PDFs) with electroweak corrections. The aim of this thesis is to provide an exhaustive description of the theoretical framework and the technical implementation…

High Energy Physics - Phenomenology · Physics 2015-09-03 Stefano Carrazza

In this work we present an efficient construction of baryon interpolating fields for lattice QCD computations of two and three point functions. These are essential building blocks of computations of nucleon parton distribution functions…

High Energy Physics - Lattice · Physics 2020-11-24 Eloy Romero , Kostas Orginos

We construct a set of parton distribution functions (PDFs) in which fixed-order NLO and NNLO calculations are supplemented with soft-gluon (threshold) resummation up to NLL and NNLL accuracy respectively, suitable for use in conjunction…

High Energy Physics - Phenomenology · Physics 2015-10-13 Marco Bonvini , Simone Marzani , Juan Rojo , Luca Rottoli , Maria Ubiali , Richard D. Ball , Valerio Bertone , Stefano Carrazza , Nathan P. Hartland

Parton Distribution Functions (PDFs) model the parton content of the proton. Among the many collaborations which focus on PDF determination, NNPDF pioneered the use of Neural Networks to model the probability of finding partons (quarks and…

Computational Physics · Physics 2020-07-21 Juan M Cruz-Martinez , Stefano Carrazza , Roy Stegeman

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

A recent study by Wang {\it et al.}(arXiv:2309.01417) proposed a novel connection between the nature of the parton distribution function (PDF) and the characteristics of its moments. In this study, we apply these findings to analyze the…

High Energy Physics - Phenomenology · Physics 2024-07-16 Xiaobin Wang , Zexin Wu , Minghui Ding , Lei Chang

We present a determination of the parton distributions of the nucleon from a global set of hard scattering data using the NNPDF methodology at LO and NNLO in perturbative QCD, thereby generalizing to these orders the NNPDF2.1 NLO parton…

The formulas directly connecting parton distribution functions (PDFs) and fragmentation functions (FFs) at the next to leading order (NLO) QCD with the same quantities at the leading order (LO) are derived. These formulas are universal,…

High Energy Physics - Phenomenology · Physics 2013-06-12 O. Yu. Shevchenko

Parton distribution functions (PDFs) describe the inner, non-perturbative structure of hadrons. Their computation involves matrix elements with a Wilson line along a direction on the light cone, posing significant challenges in Euclidean…

High Energy Physics - Lattice · Physics 2026-03-13 Mari Carmen Bañuls , Krzysztof Cichy , C. -J. David Lin , Manuel Schneider

We present a new QCD analysis of parton distribution functions (PDFs) at the next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). In the present paper, the role of special types of experimental measurements for extracting…

High Energy Physics - Phenomenology · Physics 2024-05-20 Majid Azizi , Ali Khorramian , Saeid Paktinat Mehdiabadi

In global PDF analyses, parton distribution functions (PDFs) are parametrised at a fixed input scale $Q_0$ and evolved to higher scales using the DGLAP equations. Since QCD evolution is fully determined within perturbation theory, the…

High Energy Physics - Phenomenology · Physics 2025-11-13 Ivan A. Godino , Eva D. Z. Groenendijk , Tanjona R. Rabemananjara

Transverse momentum dependent parton distribution functions (TMDPDFs) provide a unique probe of the three-dimensional spin structure of hadrons. We construct spin-dependent quasi-TMDPDFs that are amenable to lattice QCD calculations and…

High Energy Physics - Phenomenology · Physics 2020-10-02 Markus A. Ebert , Stella T. Schindler , Iain W. Stewart , Yong Zhao

We present LO, NLO and NNLO sets of parton distribution functions (PDFs) of the proton determined from global analyses of the available hard scattering data. These MMHT2014 PDFs supersede the `MSTW2008' parton sets, but are obtained within…

High Energy Physics - Phenomenology · Physics 2015-06-11 L. A. Harland-Lang , A. D. Martin , P. Motylinski , R. S. Thorne

We consider the impact that can be made on our understanding of parton distributions (PDFs) and QCD from early measurements at the LHCb experiment. The high rapidity values make the experiment uniquely suited to a detailed study of small-x…

High Energy Physics - Phenomenology · Physics 2008-08-14 R. S. Thorne , A. D. Martin , W. J. Stirling , G. Watt