English
Related papers

Related papers: Parton distribution functions with QED corrections

200 papers

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

The accurate determination of the Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson…

We present {\tt SKMHS22}, a new set of diffractive parton distribution functions (PDFs) and their uncertainties at next-to-leading-order accuracy in perturbative QCD within the {\tt xFitter} framework. We describe all available diffractive…

High Energy Physics - Phenomenology · Physics 2022-10-05 Maral Salajegheh , Hamzeh Khanpour , Ulf-G Meißner , Hadi Hashamipour , Maryam Soleymaninia

Since the first determination of a structure function many decades ago, all methodologies used to determine structure functions or parton distribution functions (PDFs) have employed a common prefactor as part of the parametrization. The…

High Energy Physics - Phenomenology · Physics 2022-03-09 Stefano Carrazza , Juan M. Cruz-Martinez , Roy Stegeman

Twist-3 collinear parton distribution functions (PDFs) are matrix elements of quark-gluon-quark or three-gluons light-cone operators. They depend on three momentum fraction variables, which are restricted to a hexagon region, and the…

High Energy Physics - Phenomenology · Physics 2024-07-10 Simone Rodini , Lorenzo Rossi , Alexey Vladimirov

We discuss the combined effect of QED and QCD corrections to the evolution of parton distributions. We extend the available knowledge of the Altarelli-Parisi splitting functions to one order higher in QED, and provide explicit expressions…

High Energy Physics - Phenomenology · Physics 2017-11-15 Daniel de Florian , German F. R. Sborlini , German Rodrigo

The high-energy tails of charged- and neutral-current Drell-Yan processes provide important constraints on the light quark and anti-quark parton distribution functions (PDFs) in the large-x region. At the same time, short-distance new…

High Energy Physics - Phenomenology · Physics 2021-08-04 Admir Greljo , Shayan Iranipour , Zahari Kassabov , Maeve Madigan , James Moore , Juan Rojo , Maria Ubiali , Cameron Voisey

QCD corrections to the QED formula for parton distribution functions of the longitudinal virtual photon are derived in the leading--logarithmic approximation. It is shown that the resulting PDF satisfy the same homogeneous evolution…

High Energy Physics - Phenomenology · Physics 2009-10-31 Jiri Chyla

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

We discuss a test of the generalization power of the methodology used in the determination of parton distribution functions (PDFs). The "future test" checks whether the uncertainty on PDFs, in regions in which they are not constrained by…

High Energy Physics - Phenomenology · Physics 2021-04-21 Juan Cruz-Martinez , Stefano Forte , Emanuele R. Nocera

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 extend the existing leading (LO), next-to-leading (NLO), and next-to-next-to-leading order (NNLO) NNPDF4.0 sets of parton distribution functions (PDFs) to approximate next-to-next-to-next-to-leading order (aN$^3$LO). We construct an…

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

The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a…

High Energy Physics - Lattice · Physics 2025-06-06 Huey-Wen Lin

Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon splitting…

High Energy Physics - Phenomenology · Physics 2016-08-08 Florian Lyonnet , Aleksander Kusina , Tomáš Ježo , Karol Kovařík , Fred Olness , Ingo Schienbein , Ji-Young Yu

We show how to account for correlations between theoretical uncertainties incorporated in parton distribution function (PDF) fits, and the theoretical uncertainties in the predictions made using these PDFs. We demonstrate by explicit…

High Energy Physics - Phenomenology · Physics 2021-10-04 Richard D. Ball , Rosalyn L. Pearson

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

The determination of the parton distribution functions (PDFs) of the proton will be an essential input for the physics program of a future 100 TeV hadron collider. The unprecedented center-of-mass energy will require knowledge of PDFs in…

High Energy Physics - Phenomenology · Physics 2016-05-27 Juan Rojo

We present recent results of the NNPDF collaboration on a full DIS analysis of Parton Distribution Functions (PDFs). Our method is based on the idea of combining a Monte Carlo sampling of the probability measure in the space of PDFs with…

High Energy Physics - Phenomenology · Physics 2008-05-21 NNPDF Collaboration , M. Ubiali , R. D. Ball , L. Del Debbio , S. Forte , A. Guffanti , J. I. Latorre , A. Piccione , J. Rojo

We apply the Lagrange Multiplier method to study the uncertainties of physical predictions due to the uncertainties of parton distribution functions (PDFs), using the cross section for W production at a hadron collider as an archetypal…

High Energy Physics - Phenomenology · Physics 2009-09-25 D. Stump , J. Pumplin , R. Brock , D. Casey , J. Huston , J. Kalk , H. L. Lai , W. K. Tung