Speaker
Description
One of the key goals of the LHC physics program is the precise determination of the Higgs boson couplings to fermions across all generations. While couplings to third-generation fermions have been established, those to light quarks remain largely unconstrained. Rare exclusive radiative decays of the Higgs boson, such as H → ρ/ϕ/K⁰ + γ, provide a unique and direct probe of the Yukawa couplings to the u, d, and s quarks, as well as sensitivity to possible physics beyond the Standard Model that could enhance these processes. Using the full Run-2 dataset collected by the CMS experiment, searches for the decays H → ρ/ϕ/K⁰ + γ have been performed, targeting final states with a high-energy photon and a light vector meson reconstructed from charged hadrons. These analyses face significant experimental challenges due to the extremely small expected branching fractions and the presence of large backgrounds. Sensitivity is enhanced by combining multiple Higgs boson production modes and by exploiting the distinctive kinematic and topological properties of the exclusive final states.