CMS-HIG-21-016
Search for exotic Higgs boson decays H → AA → 4γ with events containing two merged diphotons in proton-proton collisions at √s = 13 TeV
The first direct search for exotic Higgs boson decays H → AA, A → γγ in events with two photon-like objects is presented. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photon-like object. Data collected by the CMS experiment at √s = 13 TeV corresponding to an integrated luminosity of 136 fb−1 are analyzed. No excess above the estimated background is found. Upper limits on the branching fraction B(H → AA → 4γ) of (0.9-3.3) × 10−3 are set at 95% confidence level for masses of A in the range 0.1-1.2 GeV.