Search for new physics in the final state with a single photon and large missing transverse momentum in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for new physics with a single photon and missing transverse momentum in proton-proton collisions at 13 TeV, setting the most stringent limits to date on related models.

Contribution

It combines new 2017-2018 data with previous results to improve constraints on dark matter and extra dimension models using photon plus missing energy signatures.

Findings

No significant deviations from the Standard Model were observed.

Up to 14% improvement in exclusion reach for dark matter mediator masses.

Most stringent constraints to date on parameters of dark matter and extra dimension models.

Abstract

A search for new physics in events featuring a single photon and missing transverse momentum is presented, using proton-proton $\sqrt{s}$ = 13 TeV collision data corresponding to an integrated luminosity of 101 fb$^{-1}$ collected by the CMS experiment at the CERN LHC between 2017 and 2018. This analysis, combined with a previous study of 36 fb$^{-1}$ of 2016 data (totaling 137 fb$^{-1}$), reveals no significant deviations from standard model expectations. The results are then used to establish 95% confidence level limits on parameters in theoretical models involving dark matter and large extra dimensions. Compared to the 2016-only analysis, this search achieves up to a 14% improvement in exclusion reach for mediator masses in simplified dark matter models, along with 11% and 10% enhancements in the limits on the effective field theory suppression scale and the fundamental Planck scale, respectively. These results are the most stringent constraints on these parameters to date.