Search for Heavy Neutral MSSM Higgs Bosons with CMS: Reach and Higgs-Mass Precision

The search for MSSM Higgs bosons will be an important goal at the LHC. We analyze the search reach of the CMS experiment for the heavy neutral MSSM Higgs bosons with an integrated luminosity of 30 or 60 fb^-1. This is done by combining the latest results for the CMS experimental sensitivities based on full simulation studies with state-of-the-art theoretical predictions of MSSM Higgs-boson properties. The results are interpreted in MSSM benchmark scenarios in terms of the parameters tan_beta and the Higgs-boson mass scale, M_A. We study the dependence of the 5 sigma discovery contours in the M_A-tan_beta plane on variations of the other supersymmetric parameters. The largest effects arise from a change in the higgsino mass parameter mu, which enters both via higher-order radiative corrections and via the kinematics of Higgs decays into supersymmetric particles. While the variation of $\mu$ can shift the prospective discovery reach (and correspondingly the ``LHC wedge'' region) by about Delta tan_beta = 10, we find that the discovery reach is rather stable with respect to the impact of other supersymmetric parameters. Within the discovery region we analyze the accuracy with which the masses of the heavy neutral Higgs bosons can be determined. We find that an accuracy of 1-4% should be achievable, which could make it possible in favourable regions of the MSSM parameter space to experimentally resolve the signals of the two heavy MSSM Higgs bosons at the LHC.