Search for the Higgs boson decays to a ρ0, ϕ, or K⁎0 meson and a photon in proton-proton collisions at s=13TeV

Abstract

Three rare decay processes of the Higgs boson to a $\rho {\left(770\right)}^0$, $\varphi \left(1020\right)$, or $K^{⁎}{\left(892\right)}^0$ meson and a photon are searched for using $\sqrt{s}=13\text{TeV}$ 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${\text{fb}}^{-1}$, 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 $\rho {\left(770\right)}^0\gamma$, $\varphi \left(1020\right)\gamma$, and $K^{⁎}{\left(892\right)}^0\gamma$ 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 $\rho {\left(770\right)}^0\gamma$ and $\varphi \left(1020\right)\gamma$ channels, these are the most stringent experimental limits to date.