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Parton distribution functions (PDFs) with QED corrections extracted from the QED$\otimes$QCD DGLAP evolution equations in the framework of "valon" model. Our results for the PDFs with QED corrections in this phenomenological model are in…

High Energy Physics - Phenomenology · Physics 2017-10-25 Marzieh Mottaghizadeh , Fatemeh Taghavi Shahri , Parvin Eslami

We extract the ratio of the down (d) and up (u) parton distribution functions (PDF's) from the ratio of deuteron and proton structure function F_2(d)/F_2(p) measured by NMC. We use corrections for nuclear binding effects in the deuteron,…

High Energy Physics - Phenomenology · Physics 2007-05-23 U. K. Yang , A. Bodek

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

In this talk we summarize main results of a recent determination of the polarized deeply inelastic parton distributions to NLO from the world data. In the analysis the LO and NLO parton densities and their $1\sigma$ statistical errors were…

High Energy Physics - Phenomenology · Physics 2015-06-25 J. Blümlein , H. Böttcher

We present the first NNPDF full set of Parton Distribution Functions from a comprehensive DIS analysis. This approach, combining a Monte Carlo sampling of the probability measure in the space of PDFs with the use of neural networks as…

High Energy Physics - Phenomenology · Physics 2009-11-13 Maria Ubiali

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 a comprehensive new global QCD analysis of unpolarized parton distribution functions (PDFs) based upon proton, deuteron and $A\!=\!3$ data, including the latest inclusive deep-inelastic scattering (DIS) measurements from…

High Energy Physics - Phenomenology · Physics 2026-05-04 C. Cocuzza , W. Melnitchouk , N. Sato , A. W. Thomas

We perform the analysis of existing light-targets deep-inelastic-scattering (DIS) data in the leading-order (LO), next-to-leading-order (NLO), and next-to-next-to-leading-order (NNLO) QCD approximations and extract PDFs simultaneously with…

High Energy Physics - Phenomenology · Physics 2009-11-07 Sergey Alekhin

Nuclear parton distribution functions (NPDFs) are determined by a global analysis of experimental measurements on structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross section ratios \sigma_{DY}^A/\sigma_{DY}^{A'}, and their…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Hirai , S. Kumano , T. -H. Nagai

We discuss the influence of fixed target Drell-Yan data on the extraction of parton distribution functions at next-to-next-to-leading order (NNLO) in QCD. When used in a parton distribution fit, the Drell-Yan (DY) data constrain sea quark…

High Energy Physics - Phenomenology · Physics 2008-11-26 Sergey Alekhin , Kirill Melnikov , Frank Petriello

A new QCD analysis for nuclear parton distribution functions (nPDFs) at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) is presented. The framework of the analysis, including the form of the parameterization as well as…

High Energy Physics - Phenomenology · Physics 2019-08-15 Marina Walt , Ilkka Helenius , Werner Vogelsang

We present the main results of our recent papers, where we derived an analytical solution of the QCD evolution equations for parton distribution functions. The valence and non-singlet quark components satisfy the Gross-Llewellyn-Smith and…

High Energy Physics - Phenomenology · Physics 2025-10-24 A. V. Kotikov , A. V. Lipatov

We present recent progress towards a global determination of parton distribution functions (PDFs) at approximate N$^3$LO (aN$^3$LO) accuracy within the NNPDF framework. We construct a parametrisation of the $\mathcal{O}(\alpha_s^4)$ QCD…

High Energy Physics - Phenomenology · Physics 2023-06-28 Felix Hekhorn , Giacomo Magni

We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and…

Nuclear parton distribution functions (nPDFs) can be determined in a global QCD analysis using a wide range of experimental data. In addition to older fixed-target deep inelastic scattering and Drell-Yan (DY) dilepton production data,…

High Energy Physics - Phenomenology · Physics 2022-07-12 Ilkka Helenius , Marina Walt , Werner Vogelsang

We have calculated the splitting functions governing the evolution of the unpolarized parton distributions of the photon at the next-to-next-to-leading order (NNLO) of massless perturbative QCD. The results, presented here mainly in terms…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Vogt , S. Moch , J. Vermaseren

Nuclear parton distribution functions (NPDFs) are determined by global analyses of experimental data on structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross-section ratios \sigma_{DY}^A/\sigma_{DY}^{A'}. The analyses are done in the…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Hirai , S. Kumano , T. -H. Nagai

Twelve measurements of inclusive cross sections of W$^\pm$ and Z boson production, performed in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, are compared with perturbative quantum chromodynamics calculations at…

High Energy Physics - Experiment · Physics 2020-06-09 CMS Collaboration

The formulas directly connecting parton distribution functions (PDFs) at the leading (LO) and the next to leading (NLO) QCD orders are applied to both unpolarized and polarized valence PDFs and produce improved LO results on these…

High Energy Physics - Phenomenology · Physics 2014-03-11 O. Yu. Shevchenko , R. R. Akhunzyanov

In this article, we present a Next-to-Leading Order (NLO) QCD analysis to study the role and influence of different schemes on simultaneous determination of the Parton Distribution Functions (PDFs) and strong coupling, $\alpha_s(M^2_Z)$. We…

High Energy Physics - Phenomenology · Physics 2017-09-26 A. Vafaee , A. N. Khorramian