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QED parton distribution functions in the MSHT20 fit

Cridge, T.; Harland-Lang, L.A.; Martin, A.D.; Thorne, R.S.

QED parton distribution functions in the MSHT20 fit Thumbnail


T. Cridge

L.A. Harland-Lang

A.D. Martin

R.S. Thorne


We present the MSHT20qed set of parton distribution functions (PDFs). These are obtained from the MSHT20 global analysis via a refit including QED corrections to the DGLAP evolution at O(α),O(ααS) and O(α2), and containing the photon PDF of the proton. As in the previous MMHT15qed study we use an input distribution for the photon that is derived from the LUXqed formulation, and find good consistency for the photon PDF with that of MMHT15qed, as well as with other recent sets. We also present a set of QED corrected neutron PDFs and accompanying photon distribution, and provide the photon PDF of the nucleons separated into elastic and inelastic contributions. We assess the general expectations for the impact of photon-initiated (PI) corrections to processes entering PDF fits, and review the effect of QED corrections on the other partons and on the fit quality, where electroweak corrections (including PI production) are appropriately added to the cross sections wherever possible. We explore the phenomenological implications of this set by comparing to a variety of benchmark cross sections, finding small but significant corrections due to the inclusion of QED effects in the PDFs.


Cridge, T., Harland-Lang, L., Martin, A., & Thorne, R. (2022). QED parton distribution functions in the MSHT20 fit. The European Physical Journal C, 82(1), Article 90.

Journal Article Type Article
Acceptance Date Jan 13, 2022
Online Publication Date Jan 29, 2022
Publication Date 2022-01
Deposit Date Mar 9, 2022
Publicly Available Date Mar 9, 2022
Journal The European Physical Journal C
Print ISSN 1434-6044
Electronic ISSN 1434-6052
Publisher SpringerOpen
Peer Reviewed Peer Reviewed
Volume 82
Issue 1
Article Number 90


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