eprintid: 10195907 rev_number: 9 eprint_status: archive userid: 699 dir: disk0/10/19/59/07 datestamp: 2024-08-19 08:55:19 lastmod: 2024-08-19 08:55:19 status_changed: 2024-08-19 08:55:19 type: article metadata_visibility: show sword_depositor: 699 creators_name: Cridge, Thomas creators_name: Harland-Lang, Lucian A creators_name: Thorne, Robert S title: Combining QED and approximate N3LO 3 LO QCD corrections in a global PDF fit: MSHT20qed_an3lo PDFs ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F60 note: Copyright T. Cridge et al. This work is licensed under the Creative Commons Attribution 4.0 International License. Published by the SciPost Foundation. abstract: We present the MSHT20qed_an3lo parton distribution functions (PDFs). These result from the first global PDF analysis to combine QED and approximate N3LO (aN3LO) QCD corrections in the theoretical calculation of the PDF evolution and cross sections entering the fit. We examine the PDF impact, and find that the effect of QED is relatively mild in comparison to the aN3LO corrections, although it should still be accounted for at the level of precision now required. These QED corrections are in addition found to roughly factorise from the QCD corrections; that is, their relative impact on the PDFs is roughly the same at NNLO and aN3LO. The fit quality exhibits a very small deterioration at aN3LO upon the inclusion of QED corrections, which is rather smaller than the deterioration observed at NNLO in QCD. The impact on several cross-sections at N3LO is also examined, including the Higgs cross sections at N3LO. Finally, a LO in QCD fit that includes QED corrections is also presented: the MSHT20qed_an3lo set. date: 2024-07-30 date_type: published publisher: SCIPOST FOUNDATION official_url: http://dx.doi.org/10.21468/scipostphys.17.1.026 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2303683 doi: 10.21468/SciPostPhys.17.1.026 lyricists_name: Thorne, Robert lyricists_id: RTHOR15 actors_name: Thorne, Robert actors_id: RTHOR15 actors_role: owner funding_acknowledgements: 101002090 COLORFREE [European Research Council (ERC)]; ST/T000856/1 [STFC]; ST/X000516/1 [STFC] full_text_status: public publication: SciPost Physics volume: 17 number: 1 article_number: 026 pages: 26 issn: 2542-4653 citation: Cridge, Thomas; Harland-Lang, Lucian A; Thorne, Robert S; (2024) Combining QED and approximate N3LO 3 LO QCD corrections in a global PDF fit: MSHT20qed_an3lo PDFs. SciPost Physics , 17 (1) , Article 026. 10.21468/SciPostPhys.17.1.026 <https://doi.org/10.21468/SciPostPhys.17.1.026>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10195907/1/Thorne_SciPostPhys_17_1_026.pdf