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Combining QED and Approximate N${}^3$LO QCD Corrections in a Global PDF Fit: MSHT20qed_an3lo PDFs
by T. Cridge, L. A. Harland-Lang, R. S. Thorne
Submission summary
| Authors (as registered SciPost users): | Lucian Harland-Lang |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202404_00041v1 (pdf) |
| Date accepted: | 2024-06-19 |
| Date submitted: | 2024-04-25 15:59 |
| Submitted by: | Harland-Lang, Lucian |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Phenomenological |
Abstract
We present the MSHT20qed_an3lo parton distribution functions (PDFs). These result from the first global PDF analysis to combine QED and approximate N${}^3$LO (aN${}^3$LO) 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 aN${}^3$LO 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 aN${}^3$LO. The fit quality exhibits a very small deterioration at aN${}^3$LO 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 N${}^3$LO is also examined, including the Higgs cross section via gluon fusion at N${}^3$LO. Finally, a LO in QCD fit that includes QED corrections is also presented: the MSHT20qed_lo set.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Author comments upon resubmission
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Current status:
Editorial decision:
For Journal SciPost Physics: Publish
(status: Editorial decision fixed and (if required) accepted by authors)
Reports on this Submission
Report
The Authors have addressed most of the points that I asked them to consider. I find the manuscript clear and self-contained and completely suitable for publication. It is a pity that a QED fit at NLO requires a substantial amount of work, as it would have been nice to see the perturbative convergence of the fit, however I agree with the Authors that this goes beyond the scope of the paper. I therefore suggest the Editors to accept the paper.
Recommendation
Publish (easily meets expectations and criteria for this Journal; among top 50%)
Report
I am satisfied with the reply from the authors. I am happy to see the comparison I asked for in Fig. 3, which looks interesting. I thank the authors for their effort. I recommend this manuscript in its current status for publication.
Recommendation
Publish (surpasses expectations and criteria for this Journal; among top 10%)