Scale and isolation sensitivity of diphoton distributions at the LHC
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.
Cite
@article{arxiv.2009.11310,
title = {Scale and isolation sensitivity of diphoton distributions at the LHC},
author = {Thomas Gehrmann and Nigel Glover and Alexander Huss and James Whitehead},
journal= {arXiv preprint arXiv:2009.11310},
year = {2021}
}
Comments
35 pages, 17 figures. Additional discussion of isolation uncertainty at the end of s2.1. Version accepted for publication by JHEP