Scale and isolation sensitivity of diphoton distributions at the LHC

Gehrmann, Thomas; Glover, Nigel; Huss, Alexander; Whitehead, James

doi:10.1007/jhep01(2021)108

Scale and isolation sensitivity of diphoton distributions at the LHC

Gehrmann, Thomas; Glover, Nigel; Huss, Alexander; Whitehead, James

Authors

Thomas Gehrmann

Professor Nigel Glover e.w.n.glover@durham.ac.uk
Professor

Alexander Huss

James Whitehead

Abstract

Precision measurements of diphoton distributions at the LHC display some tension with theory predictions, obtained at next-to-next-to-leading order (NNLO) in QCD. We revisit the theoretical uncertainties arising from the approximation of the experimental photon isolation by smooth-cone isolation, and from the choice of functional form for the renormalisation and factorisation scales. We find that the resulting variations are substantial overall, and enhanced in certain regions. We discuss the infrared sensitivity at the cone boundaries in cone-based isolation in related distributions. Finally, we compare predictions made with alternative choices of dynamical scale and isolation prescriptions to experimental data from ATLAS at 8 TeV, observing improved agreement. This contrasts with previous results, highlighting that scale choice and isolation prescription are potential sources of theoretical uncertainty that were previously underestimated.

Citation

Gehrmann, T., Glover, N., Huss, A., & Whitehead, J. (2021). Scale and isolation sensitivity of diphoton distributions at the LHC. Journal of High Energy Physics, 2021(1), Article 108. https://doi.org/10.1007/jhep01%282021%29108

Journal Article Type	Article
Acceptance Date	Nov 30, 2020
Online Publication Date	Jan 19, 2021
Publication Date	2021-01
Deposit Date	Mar 15, 2021
Publicly Available Date	Mar 15, 2021
Journal	Journal of High Energy Physics
Print ISSN	1126-6708
Publisher	Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Peer Reviewed	Peer Reviewed
Volume	2021
Issue	1
Article Number	108
DOI	https://doi.org/10.1007/jhep01%282021%29108

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