Search for a narrow resonance with a mass between 10 and 70 GeV decaying to a pair of photons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for a hypothetical low-mass spin-zero particle decaying into photon pairs in proton-proton collisions at 13 TeV, setting limits on its production and decay rates.

Contribution

First search for a narrow resonance between 10 and 70 GeV decaying to diphotons at 13 TeV using a new trigger and dataset from CMS.

Findings

No significant signal observed.

Upper limits set on production cross section times branching ratio.

Results interpreted within an axion-like particle framework.

Abstract

The existence of a new spin-zero particle with a mass below the electroweak scale is predicted by several theoretical models. Searches for resonant production of photon pairs at the LHC are able to probe these models. We present a search for a narrow resonance produced through gluon fusion that decays into a pair of photons with an invariant mass between 10 and 70 GeV, using a proton-proton collision data set from the CMS experiment. This data set, corresponding to an integrated luminosity of 54.4 fb$^{-1}$, was recorded in 2018 at a center-of-mass energy of 13 TeV using a newly introduced diphoton trigger that enabled exploration of the low-mass diphoton spectrum. No significant excess above the expected background is observed. Upper limits are set on the product of the gluon fusion production cross section and the branching fraction of the diphoton decay of a narrow resonance. An interpretation of these limits within an effective field theory framework for axion-like particles is also provided.