Search for the Higgs boson decays to a $\rho^0$, $\phi$, or K$^{*0}$ meson and a photon in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This study searches for rare Higgs boson decays into specific mesons plus a photon using 13 TeV proton-proton collision data, setting the most stringent limits to date on these decay modes.

Contribution

First search for Higgs decays to a meson and a photon involving $ ho^0$, $$, or $ ext{K}^*$ mesons at 13 TeV with new upper limits.

Findings

No significant excess observed above background.

Upper limits on branching fractions are set at 3.7×10^{-4}, 3.0×10^{-4}, and 3.0×10^{-4}.

Most stringent limits to date for $ ho^0 ext{ } ext{and} ext{ }$ channels.

Abstract

Three rare decay processes of the Higgs boson to a $\rho$(770)$^0$, $\phi$(1020), or K$^{*}$(892)$^0$ meson and a photon are searched for using $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the CMS experiment at the LHC. Events are selected assuming the mesons decay into a pair of charged pions, a pair of charged kaons, or a charged kaon and pion, respectively. Depending on the Higgs boson production mode, different triggering and reconstruction techniques are adopted. The analyzed data sets correspond to integrated luminosities up to 138 fb$^{-1}$, depending on the reconstructed final state. After combining various data sets and categories, no significant excess above the background expectations is observed. Upper limits at 95% confidence level on the Higgs boson branching fractions into $\rho$(770)$^0$$\gamma$, $\phi$(1020)$\gamma$, and K$^{*}$(892)$^0\gamma$ are determined to be 3.7 $\times$ 10$^{-4}$, 3.0 $\times$ 10$^{-4}$, and 3.0 $\times$ 10$^{-4}$, respectively. In case of the $\rho$(770)$^0$$\gamma$ and $\phi$(1020)$\gamma$ channels, these are the most stringent experimental limits to date.