Physical Review Letters, cilt.131, sa.10, 2023 (SCI-Expanded)
We present the first direct search for exotic Higgs boson decays Formula Presented, Formula Presented in events with two photonlike objects. The hypothetical particle Formula Presented is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at Formula Presented corresponding to an integrated luminosity of Formula Presented. No excess above the estimated background is found. We set upper limits on the branching fraction Formula Presented of Formula Presented at 95% confidence level for masses of Formula Presented in the range 0.1-1.2 GeV.