Search for exotic Higgs boson decays H $\to$ $\mathcal{A}\mathcal{A}$ $\to$ 4$\gamma$ with events containing two merged diphotons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports the first direct search for exotic Higgs decays into a pair of low-mass particles each decaying into merged diphotons, using CMS data at 13 TeV, setting upper limits on the branching fraction.

Contribution

It introduces the first direct search for H → AA → 4γ with merged diphoton objects, providing new constraints on such exotic decay modes.

Findings

No excess above background observed.

Upper limits set on branching fraction: (0.9-3.3) × 10^{-3}.

Search covers A mass range 0.1-1.2 GeV.

Abstract

We present the first direct search for exotic Higgs boson decays H $\to$ $\mathcal{A}\mathcal{A}$, $\mathcal{A}$ $\to$ $\gamma\gamma$ in events with two photonlike objects. The hypothetical particle $\mathcal{A}$ 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 $\sqrt{s}$ = 13 TeV corresponding to an integrated luminosity of 136 fb$^{-1}$. No excess above the estimated background is found. We set upper limits on the branching fraction $\mathcal{B}$(H $\to$ $\mathcal{A}\mathcal{A}$ $\to$ 4$\gamma$) of (0.9-3.3) $\times$ 10$^{-3}$ at 95% confidence level for masses of $\mathcal{A}$ in the range 0.1-1.2 GeV.