eprintid: 10152043 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/15/20/43 datestamp: 2022-07-14 11:29:20 lastmod: 2022-07-14 11:29:20 status_changed: 2022-07-14 11:29:20 type: article metadata_visibility: show sword_depositor: 699 creators_name: Ball, Richard D creators_name: Butterworth, Jon creators_name: Cooper-Sarkar, Amanda M creators_name: Courtoy, Aurore creators_name: Cridge, Thomas creators_name: De Roeck, Albert creators_name: Feltesse, Joel creators_name: Forte, Stefano creators_name: Giuli, Francesco creators_name: Gwenlan, Claire creators_name: Harland-Lang, Lucian A creators_name: Hobbs, TJ creators_name: Hou, Tie-Jiun creators_name: Huston, Joey creators_name: McNulty, Ronan creators_name: Nadolsky, Pavel M creators_name: Nocera, Emanuele R creators_name: Rabemananjara, Tanjona R creators_name: Rojo, Juan creators_name: Thorne, Robert S creators_name: Xie, Keping creators_name: Yuan, C-P creators_name: The PDF4LHC Working Group, title: The PDF4LHC21 combination of global PDF fits for the LHC Run III* ispublished: pub divisions: C06 divisions: F60 divisions: B04 divisions: UCL keywords: Particle physics, parton distribution functions, large hadron collider, quantum chromodynamics note: Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. abstract: A precise knowledge of the quark and gluon structure of the proton, encoded by the parton distribution functions (PDFs), is of paramount importance for the interpretation of high-energy processes at present and future lepton–hadron and hadron–hadron colliders. Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin of the differences between the three global PDF sets. In particular, dedicated fits based on almost identical theory settings and input datasets are performed by the three groups, highlighting the role played by the respective fitting methodologies. We compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15, demonstrating their good overall consistency and a modest reduction of PDF uncertainties for key LHC processes such as electroweak gauge boson production and Higgs boson production in gluon fusion. We study the phenomenological implications of PDF4LHC21 for a representative selection of inclusive, fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination is made available via the LHAPDF library and provides a robust, user-friendly, and efficient method to estimate the PDF uncertainties associated to theoretical calculations for the upcoming Run III of the LHC and beyond. date: 2022-08 date_type: published publisher: IOP Publishing official_url: https://doi.org/10.1088/1361-6471/ac7216 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1965184 doi: 10.1088/1361-6471/ac7216 lyricists_name: Cridge, Thomas lyricists_id: TCRID78 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Journal of Physics G: Nuclear and Particle Physics volume: 49 number: 8 article_number: 080501 citation: Ball, Richard D; Butterworth, Jon; Cooper-Sarkar, Amanda M; Courtoy, Aurore; Cridge, Thomas; De Roeck, Albert; Feltesse, Joel; ... The PDF4LHC Working Group; + view all <#> Ball, Richard D; Butterworth, Jon; Cooper-Sarkar, Amanda M; Courtoy, Aurore; Cridge, Thomas; De Roeck, Albert; Feltesse, Joel; Forte, Stefano; Giuli, Francesco; Gwenlan, Claire; Harland-Lang, Lucian A; Hobbs, TJ; Hou, Tie-Jiun; Huston, Joey; McNulty, Ronan; Nadolsky, Pavel M; Nocera, Emanuele R; Rabemananjara, Tanjona R; Rojo, Juan; Thorne, Robert S; Xie, Keping; Yuan, C-P; The PDF4LHC Working Group; - view fewer <#> (2022) The PDF4LHC21 combination of global PDF fits for the LHC Run III*. Journal of Physics G: Nuclear and Particle Physics , 49 (8) , Article 080501. 10.1088/1361-6471/ac7216 <https://doi.org/10.1088/1361-6471%2Fac7216>. Green open access document_url: https://discovery-pp.ucl.ac.uk/id/eprint/10152043/1/Ball_2022_J._Phys._G__Nucl._Part._Phys._49_080501.pdf