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We examine the effect of including the `combined' HERA structure function data in the MSTW global fit for parton distribution functions (PDFs). The combined neutral-current HERA data have a significant, if not dramatic, effect, of up to…

High Energy Physics - Phenomenology · Physics 2010-11-19 R. S. Thorne , A. D. Martin , W. J. Stirling , G. Watt

We present a first global closure test of the fixed parameterisation (MSHT) approach to PDF fitting. We find that the default MSHT20 parameterisation can reproduce the features of the input set in such a closure test to well within the…

High Energy Physics - Phenomenology · Physics 2025-03-24 L. A. Harland-Lang , T. Cridge , R. S. Thorne

Uncertainties on parton distribution functions (PDFs) compromise discovery at the LHC for any new physics which can be described as a contact-interaction. PDF uncertainties also limit our ability to use W and Z cross-sections as an accurate…

High Energy Physics - Phenomenology · Physics 2007-07-12 A M Cooper-Sarkar

The production of $W$/$Z$-bosons in association with jets is an important test of perturbative QCD predictions and also yields information about the parton distribution functions of the proton. We present fits to determine PDFs using…

High Energy Physics - Experiment · Physics 2022-09-15 Eimear Conroy

We discuss the implications of the preliminary CMS dijet data from 5.02 TeV pp and pPb collisions for gluon PDFs of the proton and nuclei. The preliminary pp data show a discrepancy with NLO predictions using for example the CT14 PDFs. We…

High Energy Physics - Phenomenology · Physics 2018-06-22 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen

We report on the progress in updating our global analysis of nuclear PDFs. In particular, we will discuss the inclusion of double differential 5.02 TeV dijet and D-meson measurements, as well as 8.16 TeV W-production data from p-Pb…

High Energy Physics - Phenomenology · Physics 2021-09-22 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen , Carlos A. Salgado

This document is intended as a study of benchmark cross sections at the LHC (at 7 TeV) at NLO using modern parton distribution functions currently available from the 6 PDF fitting groups that have participated in this exercise. It also…

We present predictions for relevant LHC observables obtained with the NNPDF2.0 set. We compute the combined PDFs uncertainties on these observables, and show that combining errors in quadrature yields an excellent approximation to exact…

High Energy Physics - Phenomenology · Physics 2010-05-05 Maria Ubiali , Richard D. Ball , Luigi Del Debbio , Stefano Forte , Alberto Guffanti , José I. Latorre , Juan Rojo

In this paper we present a study of in-medium jet modifications performed with JEWEL and PYTHIA 6.4, focusing on the uncertainties related to variations of the perturbative scales and nuclear parton distribution functions (PDFs) and on the…

High Energy Physics - Phenomenology · Physics 2021-04-21 A. Andronic , J. Honermann , M. Klasen , C. Klein-Bösing , J. Salomon

We present results from a detailed assessment of the ultimate constraining power of LHC data on the PDFs that can be expected from the complete dataset, in particular after the High-Luminosity (HL) phase. To achieve this, HL-LHC pseudo-data…

High Energy Physics - Phenomenology · Physics 2019-07-11 Shaun Bailey

We determine the strong coupling alpha_s at NNLO in perturbative QCD using the global dataset input to the NNPDF2.1 NNLO parton fit: data from neutral and charged current deep-inelastic scattering, Drell-Yan, vector boson production and…

High Energy Physics - Phenomenology · Physics 2015-05-30 Richard D. Ball , Valerio Bertone , Luigi Del Debbio , Stefano Forte , Alberto Guffanti , Jose I. Latorre , Simone Lionetti , Juan Rojo , Maria Ubiali

New hard-scattering measurements from the LHC proton-lead run have the potential to provide important constraints on the nuclear parton distributions and thus contributing to a better understanding of the initial state in heavy ion…

High Energy Physics - Phenomenology · Physics 2015-06-17 Nestor Armesto , Juan Rojo , Carlos A. Salgado , Pia Zurita

Proton-proton collisions at the LHC generate high-intensity collimated beams of forward neutrinos up to TeV energies. Their recent observations and the initiation of a novel LHC neutrino program motivate investigations of this previously…

High Energy Physics - Phenomenology · Physics 2024-12-04 Toni Mäkelä

A complete understanding of jet dynamics is greatly enabled by accurate separation of the acoustically efficient wavepackets from their higher-energy convecting turbulent counterparts. Recent developments using Momentum Potential Theory…

Fluid Dynamics · Physics 2022-04-20 Chitrarth Prasad , Datta Gaitonde

Detailed studies have been carried out on the impact of the LHC top quark pair production data on gluon PDF, in the context of the CTEQ-TEA global PDF fit, with the ePump-updating method. The considered $t\bar{t}$ data include single…

We report on an analysis of the impact of available experimental data on hard processes in proton-lead collisions during Run I at the Large Hadron Collider on nuclear modifications of parton distribution functions. Our analysis is…

High Energy Physics - Phenomenology · Physics 2016-05-25 Néstor Armesto , Hannu Paukkunen , José Manuel Penín , Carlos A. Salgado , Pía Zurita

A simultaneous NLO QCD fit of the parton density functions (PDFs) of the proton and of the strong coupling $\alpha_{S}(M_{Z})$ is presented. The analysis is based on combined H1 and ZEUS inclusive DIS cross section measurements together…

High Energy Physics - Experiment · Physics 2015-06-03 Guenter Grindhammer

Parton Distribution Functions (PDFs) contribute significantly to the uncertainty on the determination of the top-quark pole mass and other precision measurements at the Large Hadron Collider (LHC). It is crucial to understand these…

High Energy Physics - Phenomenology · Physics 2024-01-25 Jason P. Gombas , Reinhard Schwienhorst , Binbin Dong , Jarrett Fein

A method to facilitate the consistent inclusion of cross-section measurements in proton parton density functions (PDFs) fits in NLO QCD has been developed. It allows the a posteriori variation of the renormalisation and factorisation scales…

High Energy Physics - Phenomenology · Physics 2010-10-11 Pavel Starovoitov

We study several sources of theoretical uncertainty in the determination of parton distributions (PDFs) which may affect current PDF sets used for precision physics at the Large Hadron Collider, and explain discrepancies between them. We…

High Energy Physics - Phenomenology · Physics 2013-05-09 The NNPDF Collaboration , Richard D. Ball , Valerio Bertone , Luigi Del Debbio , Stefano Forte , Alberto Guffanti , Juan Rojo , Maria Ubiali