New LHC bound on low-mass diphoton resonances

TL;DR

This paper establishes new constraints on low-mass diphoton resonances at the LHC, improving limits on axion-like particles in the 10-65 GeV range and discussing potential search strategies.

Contribution

It provides the first comprehensive bound on low-mass diphoton resonances using existing LHC data and estimates sensitivities for future dedicated searches.

Findings

Sets the current best limit on axion-like particles between 10-65 GeV.

Proposes potential sensitivities for future LHC diphoton searches at 7, 8, and 14 TeV.

Comments on the possible axion-like particle explanation of CMS low-mass excesses.

Abstract

We derive a new bound on diphoton resonances using inclusive diphoton cross section measurements at the LHC, in the so-far poorly constrained mass range between the Upsilon and the SM Higgs. This bound sets the current best limit on axion-like particles that couple to gluons and photons, for masses between 10 and 65 GeV. We also estimate indicative sensitivities of a dedicated diphoton LHC search in the same mass region, at 7, 8 and 14 TeV. As a byproduct of our analysis, we comment on the axion-like particle interpretation of the CMS excesses in low-mass dijet and diphoton searches.