Decays of Higgs bosons tobb¯,ττ¯,andcc¯as signatures of supersymmetry andCPphases

Abstract

The branching ratio of the lightest Higgs boson decay into $b\overline{b},$ $\ensuremath{\tau}\overline{\ensuremath{\tau}}$ and $c\overline{c}$ is sensitive to supersymmetric effects. We include in this work the effects of $\mathrm{CP}$ phases on the Higgs boson decays. Specifically we compute the deviation of the $\mathrm{CP}$ phase dependent branching ratio from the standard model result. The analysis includes the full one loop corrections of fermion masses including $\mathrm{CP}$ phases involving the gluino, the chargino and the neutralino exchanges. The analysis shows that the supersymmetric effects with $\mathrm{CP}$ phases can change the branching ratios by as much as 100% for the lightest Higgs boson decay into $b\overline{b}$ and $\ensuremath{\tau}\overline{\ensuremath{\tau}}$ with similar results holding for the heavier Higgs boson decays. A detailed analysis is also given for the effects of $\mathrm{CP}$ phases on the Higgs boson decays into $c\overline{c}.$ The deviations of ${R}_{b/\ensuremath{\tau}}$ and ${R}_{b/c}$ from the standard model result are investigated as a possible signature of supersymmetry and $\mathrm{CP}$ effects. Thus a measurement of the decays of the Higgs boson into $b\overline{b},$ $\ensuremath{\tau}\overline{\ensuremath{\tau}}$ and $c\overline{c}$ may provide important clues regarding the existence of supersymmetry and $\mathrm{CP}$ phases.