  We propose using the lightest CP-even Higgs boson in the minimal
supersymmetric standard model (MSSM) to probe the stop sector. Unlike measuring
stop masses in production/decay processes which requires knowledge of masses
and mixing angles of other superparticles, the strategy depends little on
supersymmetric parameters other than those in the stop sector in a large region
of parameter space. We show that measurements of the Higgs mass and the
production rate in the gluon fusion channel, the dominant channel at the LHC,
allow for determination of two parameters in the stop mass-squared matrix,
including the off-diagonal mixing term. This proposal is very effective when
stops are light and their mixing is large, which coincides with the region
where the electroweak symmetry breaking is minimally fine tuned. We also argue
that a lightest CP-even Higgs mass in the upper range of allowed values and a
production rate significantly smaller than in the standard model would be
difficult to reconcile within the MSSM, except in extreme corners of the
parameter space.
