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Representing the parton distribution functions (PDFs) of the proton and other hadrons through flexible, high-fidelity parametrizations has been a long-standing goal of particle physics phenomenology. This is particularly true since the…

High Energy Physics - Phenomenology · Physics 2024-06-21 Brandon Kriesten , T. J. Hobbs

We report on EPPS16, the first global analysis of nuclear parton distribution functions (nPDFs) to include LHC data. Also for the first time, a full flavour dependence of nPDFs is allowed. While the included Z and W data are found to have…

High Energy Physics - Phenomenology · Physics 2018-02-05 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen , Carlos A. Salgado

In LHC searches for new and rare phenomena the top-associated channel $pp \to t\overline{t}W^\pm +X$ is a challenging background that multilepton analyses must overcome. Motivated by sustained measurements of enhanced rates of same-sign and…

High Energy Physics - Phenomenology · Physics 2020-12-08 Stefan von Buddenbrock , Richard Ruiz , Bruce Mellado

The Fortran LHAPDF library has been a long-term workhorse in particle physics, providing standardised access to parton density functions for experimental and phenomenological purposes alike, following on from the venerable PDFLIB package.…

High Energy Physics - Phenomenology · Physics 2015-06-23 Andy Buckley , James Ferrando , Stephen Lloyd , Karl Nordstrom , Ben Page , Martin Ruefenacht , Marek Schoenherr , Graeme Watt

We discuss the recent CMS Collaboration measurement of $W^\pm$ boson production in p+Pb collisions at 8.16 TeV in terms of the constraining power on nuclear parton distribution functions (PDFs). The impact of the free-proton PDF…

High Energy Physics - Phenomenology · Physics 2022-04-13 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen , Carlos A. Salgado

We evaluate the uncertainties due to nuclear effects in global fits of proton parton distribution functions (PDFs) that utilise deep-inelastic scattering and Drell-Yan data on deuterium targets. To do this we use an iterative procedure to…

High Energy Physics - Phenomenology · Physics 2021-02-03 Richard D. Ball , Emanuele R. Nocera , Rosalyn L. Pearson

The xFitter project (former HERAFitter project) is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton for many different kinds of analyses in Quantum…

High Energy Physics - Phenomenology · Physics 2017-09-06 Francesco Giuli

We quantify the impact of LHCb D-meson measurements at $\sqrt{s}=5 \, {\rm TeV}$ on the EPPS16 and nCTEQ15 nuclear PDFs. In our study, the theoretical description of D-meson production is based on the recently developed SACOT-$m_{\rm T}$…

High Energy Physics - Phenomenology · Physics 2019-06-11 Kari J. Eskola , Ilkka Helenius , Petja Paakkinen , Hannu Paukkunen

Multi-modal large language models (LLMs) have shown remarkable performance in various natural language processing tasks, including data extraction from documents. However, the accuracy of these models can be significantly affected by…

Computation and Language · Computer Science 2024-06-18 Anjanava Biswas , Wrick Talukdar

We report the results of a new global QCD analysis including deep-inelastic scattering data off $^1$H, $^2$H, $^3$H, and $^3$He targets. Nuclear corrections are treated in terms of a nuclear convolution approach with off-shell bound…

High Energy Physics - Phenomenology · Physics 2023-06-14 S. I. Alekhin , S. A. Kulagin , R. Petti

We investigate the impact of theoretical uncertainties on the accuracy of measurements involving hadronic jets. The analysis is performed using events with a Z boson and a single jet observed in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96…

High Energy Physics - Experiment · Physics 2014-11-21 A. A. Paramonov , F. Canelli , M. D'Onofrio , H. J. Frisch , S. Mrenna

Modern global analyses of the structure of the proton include collider measurements which probe energies well above the electroweak scale. While these provide powerful constraints on the parton distribution functions (PDFs), they are also…

High Energy Physics - Phenomenology · Physics 2019-10-02 Stefano Carrazza , Celine Degrande , Shayan Iranipour , Juan Rojo , Maria Ubiali

We study the sources of systematic errors in the measurement of the W to lepton and neutrino cross-sections at the LHC. We consider the systematic errors in both the total cross-section and acceptance for anticipated experimental cuts. We…

High Energy Physics - Phenomenology · Physics 2009-02-18 Nadia E. Adam , Valerie Halyo , Scott A. Yost , Wenhan Zhu

Recent ATLAS data significantly extend the exclusion limits for supersymmetric particles. We examine the impact of such data on global fits of the constrained minimal supersymmetric standard model (CMSSM) to indirect and cosmological data.…

High Energy Physics - Phenomenology · Physics 2015-03-19 B. C. Allanach , T. J. Khoo , C. G. Lester , S. L. Williams

We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the…

As the current nuclear PDF analyses are mainly constrained by fixed-target Drell-Yan and deeply inelastic scattering data only the quark nuclear modifications at fairly large $x$ values are in a good control. Inclusive pion production in…

High Energy Physics - Phenomenology · Physics 2015-10-02 Ilkka Helenius , Hannu Paukkunen , Kari J. Eskola

A method to facilitate the consistent inclusion of cross-section measurements based on complex final-states from HERA, TEVATRON and the LHC in proton parton density function (PDF) fits has been developed. This can be used to increase the…

High Energy Physics - Phenomenology · Physics 2014-11-20 Tancredi Carli , Dan Clements , Amanda Cooper-Sarkar , Claire Gwenlan , Gavin P. Salam , Frank Siegert , Pavel Starovoitov , Mark Sutton

We report on EPPS16 - the first analysis of NLO nuclear PDFs where LHC p-Pb data (Z, W, dijets) have been directly used as a constraint. In comparison to our previous fit EPS09, also data from neutrino-nucleus deeply-inelastic scattering…

High Energy Physics - Phenomenology · Physics 2017-09-26 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen , Carlos A. Salgado

In this work, we demonstrate the constraining power of the tomographic weak lensing convergence PDF for StageIV-like source galaxy redshift bins and shape noise. We focus on scales of $10$ to $20$ arcmin in the mildly nonlinear regime,…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-16 Lina Castiblanco , Cora Uhlemann , Joachim Harnois-Déraps , Alexandre Barthelemy

The PDF4LHC group has benchmarked six modern PDF sets and used them to make predictions for W,Z and Higgs production at the LHC. The reasons why predictions differ are examined and recent updates to the PDFs and their predictions are…

High Energy Physics - Phenomenology · Physics 2011-07-27 A M Cooper-Sarkar