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We investigate the parton distribution functions (PDFs) of the pion and the kaon by combining quantum chromodynamics (QCD) evolution with the basis light front quantization. The initial PDFs result from the light front wave functions…

Nuclear Theory · Physics 2020-07-23 Jiangshan Lan , Chandan Mondal , Shaoyang Jia , Xingbo Zhao , James P. Vary

We present a nonperturbative determination of the pion valence parton distribution function (PDF) moment ratios $\left\langle x^{n-1} \right\rangle / \left\langle x \right\rangle$ up to $n=6$, using the gradient flow in lattice QCD. As a…

Modern analysis on parton distribution functions (PDFs) requires calculations of the log-likelihood functions from thousands of experimental data points, and scans of multi-dimensional parameter space with tens of degrees of freedom. In…

High Energy Physics - Phenomenology · Physics 2022-08-24 DianYu Liu , ChuanLe Sun , Jun Gao

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

High Energy Physics - Phenomenology · Physics 2019-12-17 Marina Walt , Ilkka Helenius , Werner Vogelsang

We carry out a global QCD analysis of parton-to-pion fragmentation functions at next-to-next-to-leading order (NNLO) accuracy by performing a fit to the combined set of single-inclusive electron-positron annihilation and, for the first…

High Energy Physics - Phenomenology · Physics 2022-07-13 Ignacio Borsa , Daniel de Florian , Rodolfo Sassot , Marco Stratmann , Werner Vogelsang

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 study the changes in the short-distance quark structure of the Nambu-Goldstone boson when the long-distance symmetry-breaking scales are depleted controllably. We achieve this by studying the valence Parton Distribution Function (PDF) of…

High Energy Physics - Lattice · Physics 2021-05-04 Nikhil Karthik

We review the current status of spin-averaged and spin-dependent parton distribution functions (PDFs) of the nucleon. After presenting the formalism used to fit PDFs in modern global data analyses, we discuss constraints placed on the PDFs…

High Energy Physics - Phenomenology · Physics 2015-06-16 P. Jimenez-Delgado , W. Melnitchouk , J. F. Owens

A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed. The determinations have been carried out according to the NNPDF methodology, leading to a fit…

High Energy Physics - Phenomenology · Physics 2014-11-04 Nathan Hartland

We discuss the statistical properties of parton distributions within the framework of the NNPDF methodology. We present various tests of statistical consistency, in particular that the distribution of results does not depend on the…

We present a state-of-the-art calculation of the unpolarized pion valence-quark distribution in the framework of large-momentum effective theory (LaMET) with improved handling of systematic errors as well as two-loop perturbative matching.…

High Energy Physics - Lattice · Physics 2024-04-24 Jack Holligan , Huey-Wen Lin

We present a determination of the strong coupling $\alpha_s(m_Z)$ from a global dataset including both fixed-target and collider data from deep-inelastic scattering and a variety of hadronic processes, with a simultaneous determination of…

A new and simple statistical approach is performed to calculate the parton distribution functions (PDFs) of the nucleon in terms of light-front kinematic variables. We do not put in any extra arbitrary parameter or corrected term by hand,…

High Energy Physics - Phenomenology · Physics 2009-03-12 Yunhua Zhang , Lijing Shao , Bo-Qiang Ma

In this paper, we address the fundamental problem of line spectral estimation in a Bayesian framework. We target model order and parameter estimation via variational inference in a probabilistic model in which the frequencies are…

Information Theory · Computer Science 2017-04-05 Mihai-Alin Badiu , Thomas Lundgaard Hansen , Bernard Henri Fleury

We review strategies to unveil the primordial large-$x$ structure of the nucleons as well as the pion from hard-scattering experiments. Ideas are presented for learning about the $x\to 1$ limit of nonperturbative QCD dynamics at energy…

High Energy Physics - Phenomenology · Physics 2021-08-10 Aurore Courtoy , Pavel M. Nadolsky

An extension of the xFitter open-source program for QCD analyses is presented, allowing for a polynomial parameterization of the dependence of physical observables on theoretical parameters. This extension enables simultaneous determination…

High Energy Physics - Phenomenology · Physics 2024-12-03 XiaoMin Shen , Simone Amoroso , Jun Gao , Katerina Lipka , Oleksandr Zenaiev

We present the results of a complete leading-twist next-to-leading order (NLO) QCD analysis of the spacelike pion electromagnetic form factor at large momentum transfer Q. We have studied their dependence on the form of the pion…

High Energy Physics - Phenomenology · Physics 2009-08-25 B. Melic , B. Nizic , K. Passek

In this kick-off presentation for the "Recent developments in QCD" session at Baryons 2025 I will tie together the recent progress made on the extraction of parton distribution functions (PDFs) in lattice QCD and the long standing efforts…

High Energy Physics - Lattice · Physics 2026-04-03 Alexander Rothkopf

We present preliminary results on the determination of spin-dependent, or polarised, Parton Distribution Functions (PDFs) from all relevant inclusive polarised DIS data. The analysis is performed within the NNPDF approach, which provides a…

High Energy Physics - Phenomenology · Physics 2012-06-26 Emanuele R. Nocera , Stefano Forte , Giovanni Ridolfi , Juan Rojo

A "meta-analysis" is a method for comparison and combination of nonperturbative parton distribution functions (PDFs) in a nucleon obtained with heterogeneous procedures and assumptions. Each input parton distribution set is converted into a…

High Energy Physics - Phenomenology · Physics 2015-06-18 Jun Gao , Pavel Nadolsky