  Electroweak baryogenesis (EWBG) in the MSSM can account for the cosmological
baryon asymmetry, but only within a restricted region of the parameter space.
In particular, MSSM EWBG requires a mostly right-handed stop that is lighter
than the top quark and a standard model-like light Higgs boson. In the present
work we investigate the effects of the light stop on Higgs boson production and
decay. Relative to the standard model Higgs boson, we find a large enhancement
of the Higgs production rate through gluon fusion and a suppression of the
Higgs branching fraction into photon pairs. These modifications in the
properties of the Higgs boson are directly related to the effect of the light
stop on the electroweak phase transition, and are large enough that they can
potentially be tested at the Tevatron and the LHC.
