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Related papers: Parton distributions need representative sampling

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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

We present the first global analysis of parton distribution functions (PDFs) at approximate N$^{3}$LO in the strong coupling constant $\alpha_{s}$, extending beyond the current highest NNLO achieved in PDF fits. To achieve this, we present…

High Energy Physics - Phenomenology · Physics 2023-03-14 J. McGowan , T. Cridge , L. A. Harland-Lang , R. S. Thorne

We formulate a general approach to the inclusion of theoretical uncertainties, specifically those related to the missing higher order uncertainty (MHOU), in the determination of parton distribution functions (PDFs). We demonstrate how,…

We discuss the determination of the parton substructure of hadrons by casting it as a peculiar form of pattern recognition problem in which the pattern is a probability distribution, and we present the way this problem has been tackled and…

High Energy Physics - Phenomenology · Physics 2020-08-31 Stefano Forte , Stefano Carrazza

The recently developed "Data Set Diagonalization" method (DSD) is applied to measure compatibility of the data sets that are used to determine parton distribution functions (PDFs). Discrepancies among the experiments are found to be…

High Energy Physics - Phenomenology · Physics 2010-04-22 Jon Pumplin

The parton distribution functions (PDFs) are a non-negotiable input to almost all theory predictions at hadron colliders. In this talk, I introduce PDF determination by global analysis and discuss selected topics concerning recent relevant…

High Energy Physics - Phenomenology · Physics 2010-01-25 Graeme Watt

We examine the sources of parton distribution errors in the $W$ mass measurement, and point out shortcomings in the existing literature. Optimistic assumptions about strategies to reduce the error by normalizing to $Z$ observables are…

High Energy Physics - Phenomenology · Physics 2015-08-26 Seth Quackenbush , Zack Sullivan

We include uncertainties due to missing higher order corrections to QCD computations (MHOU) used in the determination of parton distributions (PDFs) in the recent NNPDF4.0 set of PDFs. We use our previously published methodology, based on…

We review basic ideas and recent developments on the determination of the parton substructure of the nucleon, in view of applications to precision hadron collider physics. We review the way information on parton distributions (PDFs) is…

High Energy Physics - Phenomenology · Physics 2015-03-17 Stefano Forte

We critically assess the robustness of uncertainties on parton distribution functions (PDFs) determined using neural networks from global sets of experimental data collected from multiple experiments. We view the determination of PDFs as an…

High Energy Physics - Phenomenology · Physics 2025-03-25 Andrea Barontini , Mark N. Costantini , Giovanni De Crescenzo , Stefano Forte , Maria Ubiali

The photon parton distribution function (PDF) of the proton is crucial for precise comparisons of LHC cross sections with theoretical predictions. However, it was previously affected by very large uncertainties of around ${\cal O}(100\%)$…

High Energy Physics - Phenomenology · Physics 2024-08-26 Aneesh Manohar , Paolo Nason , Gavin Salam , Giulia Zanderighi

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

We reexamine the dominant contribution of parton distribution function (PDF) uncertainties to the W mass measurement, and determine their contribution is +-39(30) MeV when running the Large Hadron Collider at 7(13) TeV. We find that…

High Energy Physics - Phenomenology · Physics 2015-08-19 Zack Sullivan , Seth Quackenbush

We present a new procedure to determine Parton Distribution Functions (PDFs), based on Markov Chain Monte Carlo (MCMC) methods. The aim of this paper is to show that we can replace the standard $\chi^2$ minimization by procedures grounded…

High Energy Physics - Phenomenology · Physics 2017-11-07 Yémalin Gabin Gbedo , Mariane Mangin-Brinet

Focusing on hadron scattering at large partonic momentum fractions $x$, we compare nonperturbative QCD predictions for the asymptotic behavior of DIS structure functions and parton distribution functions (PDFs) to the $x$ and $Q$ dependence…

High Energy Physics - Phenomenology · Physics 2021-12-30 Aurore Courtoy , Pavel M. Nadolsky

We present a new set of parton distribution functions (PDFs) based on a fully global dataset and machine learning techniques: NNPDF4.0. We expand the NNPDF3.1 determination with 44 new datasets, mostly from the LHC. We derive a novel…

Parton Density Functions (PDFs) and their uncertainties are extremely important topics for both the Tevatron and the LHC. Experiments at the Tevatron can enhance this knowledge not only by constraining the PDF fits, but also by developing…

High Energy Physics - Phenomenology · Physics 2007-05-23 D Bourilkov , R C Group , M R Whalley

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

We investigate the uncertainties of the heavy-quark parton distribution functions in the variable flavor number scheme. Because the charm- and bottom-quark parton distribution functions (PDFs) are constructed predominantly from the gluon…

High Energy Physics - Phenomenology · Physics 2008-11-26 Z. Sullivan , P. M. Nadolsky

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