The decay h0-->A0A0 in the minimal supersymmetric model.

Abstract

The decay ${h}^{0}\ensuremath{\rightarrow}{A}^{0}{A}^{0}$ (where ${h}^{0}$ and ${A}^{0}$ are the lightest $\mathrm{CP}$-even and $\mathrm{CP}$-odd Higgs bosons of a two-Higgs-doublet model) is kinematically forbidden at the tree level in the minimal supersymmetric model. However, if radiative corrections are included, the mass of ${h}^{0}$ can be larger than twice the mass of ${A}^{0}$ over part of the supersymmetric parameter space. Moreover, in this parameter regime, ${h}^{0}$ must be lighter than the $Z$. We compute the radiatively corrected width for ${h}^{0}\ensuremath{\rightarrow}{A}^{0}{A}^{0}$ to leading-logarithmic accuracy, and verify that this decay can be the dominant ${h}^{0}$ decay mode. Thus, in searches for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}^{0}{A}^{0}$ at the CERN ${e}^{+}{e}^{\ensuremath{-}}$ colliders LEP and LEP II, one must search for events with ${A}^{0}{A}^{0}{A}^{0}$ final states in order to set unambiguous limits for the ${A}^{0}$ mass.