Scale and isolation sensitivity of diphoton distributions at the LHC

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

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
• Electronic ISSN: 1029-8479
• 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
• Public URL: https://durham-repository.worktribe.com/output/1245535