Implications of the LEP Higgs Bounds for the MSSM Stop Sector

The implications of the LEP Higgs bounds on the MSSM stop masses and mixing are compared in two different regions of the Higgs parameter space. The first region is the Higgs decoupling limit, in which the bound on the mass of the lighter Higgs is $m_h \ge 114.4$ GeV, and the second region is near a non-decoupling limit with $m_h \simeq 93$ GeV, in which the masses of all the physical Higgs bosons are required to be light. Additional constraints from the electroweak $S$- and $T$-parameter and the decays $B \to X_s \gamma$ and $B_s \to \mu^+ \mu^-$, which also constrain the Higgs and/or stop sector, are considered. In some regions of the MSSM parameter space these additional constraints are stronger than the LEP Higgs bounds. Implications for the tuning of electroweak symmetry breaking are also discussed.