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.
| Original language | English |
|---|---|
| Article number | 080501 |
| Pages (from-to) | 1-95 |
| Number of pages | 95 |
| Journal | Journal of Physics G: Nuclear and Particle Physics |
| Volume | 49 |
| Issue number | 8 |
| Early online date | 5 Jul 2022 |
| DOIs | |
| Publication status | Published - Aug 2022 |
Bibliographical note
Funding Information:We are grateful to the members of the PDF4LHC community for many useful discussions in the course of the last two years. We also thank Christopher Schwan for assistance with the computation of the high invariant mass Drell-Yan. TC and RST thank the Science and Technology Facilities Council (STFC) for support via Grant Awards ST/P000274/1 and ST/T000856/1. LHL thanks STFC for support via Grant Awards ST/L000377/1 and ST/T000864/1. RDB and ERN thank the STFC for support by the Grant Awards ST/P000630/1 and ST/T000600/1. PMN is partially supported by the US Department of Energy under Grant No. DE-SC0010129. JR is partially supported by the Dutch Research Council (NWO). The research of TR has been partially supported by an ASDI grant of The Netherlands eScience Center. The work of CPY is partially supported by the US National Science Foundation under Grant No. PHY-2013791. CPY is also grateful for the support from the Wu-Ki Tung endowed chair in particle physics. AC is supported by UNAM Grant No. DGAPA-PAPIIT IN111222 and CONACyT—Ciencia de Frontera 2019 No. 51244 (FORDECYT-PRONACES). The work of KX is supported by US Department of Energy under Grant No. DE-SC0007914, US National Science Foundation under Grant No. PHY-2112829, and in part by the PITT PACC. AC-S acknowledges financial support from the Leverhulme Trust. The work of T J Hobbs was supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the US Department of Energy, Office of Science, Office of High Energy Physics. At earlier stages, support at SMU was provided by the US Department of Energy under Grant No. DE-SC0010129 as well as by a JLab EIC Center Fellowship. SF is supported by the European Research Council under the European Union’s Horizon 2020 research and innovation Programme (Grant Agreement No. 740006).
Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd.
Funding
We are grateful to the members of the PDF4LHC community for many useful discussions in the course of the last two years. We also thank Christopher Schwan for assistance with the computation of the high invariant mass Drell-Yan. TC and RST thank the Science and Technology Facilities Council (STFC) for support via Grant Awards ST/P000274/1 and ST/T000856/1. LHL thanks STFC for support via Grant Awards ST/L000377/1 and ST/T000864/1. RDB and ERN thank the STFC for support by the Grant Awards ST/P000630/1 and ST/T000600/1. PMN is partially supported by the US Department of Energy under Grant No. DE-SC0010129. JR is partially supported by the Dutch Research Council (NWO). The research of TR has been partially supported by an ASDI grant of The Netherlands eScience Center. The work of CPY is partially supported by the US National Science Foundation under Grant No. PHY-2013791. CPY is also grateful for the support from the Wu-Ki Tung endowed chair in particle physics. AC is supported by UNAM Grant No. DGAPA-PAPIIT IN111222 and CONACyT—Ciencia de Frontera 2019 No. 51244 (FORDECYT-PRONACES). The work of KX is supported by US Department of Energy under Grant No. DE-SC0007914, US National Science Foundation under Grant No. PHY-2112829, and in part by the PITT PACC. AC-S acknowledges financial support from the Leverhulme Trust. The work of T J Hobbs was supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the US Department of Energy, Office of Science, Office of High Energy Physics. At earlier stages, support at SMU was provided by the US Department of Energy under Grant No. DE-SC0010129 as well as by a JLab EIC Center Fellowship. SF is supported by the European Research Council under the European Union’s Horizon 2020 research and innovation Programme (Grant Agreement No. 740006).
Keywords
- large hadron collider
- particle physics
- parton distribution functions
- quantum chromodynamics
