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Related papers: Comments on Global Parton Analyses

200 papers

Using the recently derived NNLO cross sections \cite{Czakon:2013goa}, we provide NNLO+NNLL theoretical predictions for top quark pair production based on all the available NNLO PDF sets, and compare them with the most precise LHC and…

High Energy Physics - Phenomenology · Physics 2015-06-15 Michal Czakon , Michelangelo L. Mangano , Alexander Mitov , Juan Rojo

We study the effect of absorptive corrections due to parton recombination on the parton distributions of the proton. A more precise version of the GLRMQ equations, which account for non-linear corrections to DGLAP evolution, is derived. An…

High Energy Physics - Phenomenology · Physics 2014-11-18 G. Watt , A. D. Martin , M. G. Ryskin

The inclusion of QCD corrections to the Born amplitude of deeply virtual Compton scattering in both spacelike (DVCS) and timelike (TCS) regimes modifies the extraction process of generalized parton distributions (GPDs) from observables. In…

High Energy Physics - Phenomenology · Physics 2014-01-10 H. Moutarde , B. Pire , F. Sabatié , L. Szymanowski , J. Wagner

Double parton distribution functions (dPDF), accessible in high energy proton-proton and proton nucleus collisions, encode information on how partons inside a proton are correlated among each other and could represent a tool to explore the…

High Energy Physics - Phenomenology · Physics 2015-09-30 Matteo Rinaldi , Sergio Scopetta , Marco Traini , Vicente Vento

A new approach to global QCD analysis is developed. The main ingredients are two QCD-based evolution equations. The first one is the Balitsky-Kovchegov nonlinear equation, which sums higher twists while preserving unitarity. The second…

High Energy Physics - Phenomenology · Physics 2014-11-17 E. Gotsman , E. Levin , M. Lublinsky , U. Maor

Predictions for the angular distribution of massive quarks and leptons are presented, including QCD and QED corrections. Recent results for the fermionic part of the two-loop corrections to the electromagnetic form factors are combined with…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , A. H. Hoang , J. H. Kuhn , T. Teubner

The parton distribution functions (PDFs) which characterize the structure of the proton are currently one of the dominant sources of uncertainty in the predictions for most processes measured at the Large Hadron Collider (LHC). Here we…

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 calculate the perturbative corrections in the strong coupling to the unpolarized quark transverse-momentum dependent parton distribution function (TMDPDF) operator within a background-field framework, extending the approach of Ref. [1].…

High Energy Physics - Phenomenology · Physics 2025-07-01 Swagato Mukherjee , Vladimir V. Skokov , Andrey Tarasov , Shaswat Tiwari

The goal of this study is to find a prescription for defining parton distributions (PDFs) which are most appropriate for use in those codes where only LO matrix elements (MEs) are used, as in many Monte Carlo generators. We describe a…

High Energy Physics - Phenomenology · Physics 2008-07-15 A. Sherstnev , R. S. Thorne

The calculation of higher-order corrections in Quantum Field Theories is a challenging task. In particular, dealing with multiloop and multileg Feynman amplitudes leads to severe bottlenecks and a very fast scaling of the computational…

High Energy Physics - Phenomenology · Physics 2023-05-16 German F. R. Sborlini

I review recent progress in the NNPDF global analyses of parton distributions (PDFs) focusing on developments contributing to its new upcoming release: NNPDF4.0. The NNPDF4.0 determination represents unprecedented progress in three main…

High Energy Physics - Phenomenology · Physics 2021-04-20 Juan Rojo

We investigate the effect of extending the standard MSTW parameterisation of input parton distribution functions (PDFs) using Chebyshev polynomials. We find evidence that four powers in the polynomial are sufficient for extremely high…

High Energy Physics - Phenomenology · Physics 2013-03-18 A. D. Martin , A. J. Th. M. Mathijssen , W. J. Stirling , R. S. Thorne , B. J. A. Watt , G. Watt

We present a new analysis of parton distributions of the proton. This incorporates a wide range of new data, an improved treatment of heavy flavours and a re-examination of prompt photon production. The new set (MRST) shows systematic…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. D. Martin , R. G. Roberts , W. J. Stirling , R. S. Thorne

Updated predictions are presented for high energy neutrino and antineutrino charged and neutral current cross-sections within the conventional DGLAP formalism of NLO QCD using modern PDF fits. PDF uncertainties from model assumptions and…

High Energy Physics - Phenomenology · Physics 2011-08-18 Amanda Cooper-Sarkar , Philipp Mertsch , Subir Sarkar

We investigate enhanced EW corrections to inclusive hard processes in the TeV energy region with emphasis on the small-x situation, in which the hard scale Q is significantly smaller than the available energy \sqrt{s}= Q/x. We first propose…

High Energy Physics - Phenomenology · Physics 2014-11-18 M. Ciafaloni , P. Ciafaloni , D. Comelli

The results of perturbative QCD evaluation of the ~m_f^2/M_Z^2 contributions to the decay rates in Z--->bb and Z--->hadrons for the quark masses m_f << M_Z are presented. The recent results due to the combination of renormalization group…

High Energy Physics - Phenomenology · Physics 2009-10-28 Levan R. Surguladze

We critically examine uncertainties in parton distribution functions (PDFs) at large x arising from nuclear effects in deuterium F2 structure function data. Within a global PDF analysis, we assess the impact on the PDFs from uncertainties…

High Energy Physics - Phenomenology · Physics 2011-08-17 A. Accardi , W. Melnitchouk , J. F. Owens , M. E. Christy , C. E. Keppel , L. Zhu , J. G. Morfin

Scaling violation of inclusive jet production at small-$x$ in hadron scattering with increasing total collision energy is discussed. Perturbative QCD based on the factorisation theorem for hard processes and GLAPD evolution equations…

High Energy Physics - Phenomenology · Physics 2007-05-23 Victor T. Kim , Grigorii B. Pivovarov , James P. Vary

The perturbative QCD expansion for $J/\psi$ photoproduction appears to be unstable: the NLO correction is large (and of opposite sign) to the LO contribution. Moreover, the predictions are very sensitive to the choice of factorization and…

High Energy Physics - Phenomenology · Physics 2016-12-21 S. P. Jones , A. D. Martin , M. G. Ryskin , T. Teubner