Effect of charged scalar loops on photonic decays of a fermiophobic Higgs boson

Abstract

Higgs bosons with very suppressed couplings to fermions (``fermiophobic Higgs bosons,'' ${h}_{f}$) can decay to two photons ($\ensuremath{\gamma}\ensuremath{\gamma}$) with a branching ratio significantly larger than that expected for the standard model Higgs boson for ${m}_{{h}_{f}}<150\text{ }\text{ }\mathrm{GeV}$. Such a particle would give a clear signal at the LHC and can arise in the two Higgs doublet model (type I) in which ${h}_{f}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ is mediated by ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and charged Higgs boson (${H}^{\ifmmode\pm\else\textpm\fi{}}$) loops. We show that the ${H}^{\ifmmode\pm\else\textpm\fi{}}$ loops can cause both constructive and destructive contributions with a magnitude considerably larger than the anticipated precision in the measurement of the photonic decay channel at future hadron and lepton colliders.