The MSSM Higgs sector at a high MSUSY: reopening the low tan β regime and heavy Higgs searches

One of the main implications of the LHC discovery of a Higgs boson with a mass M-h approximate to 126GeV is that the scale of supersymmetry-breaking in the Minimal Supersymmetric Standard Model (MSSM) might be rather high, M-S >> M-Z. In this paper, we consider the high M-S regime and study the spectrum of the extended Higgs sector of the MSSM, including the LHC constraints on the mass and the rates of the observed light h state. In particular, we show that in a simplified model that approximates the important radiative corrections, the unknown scale M-S (and some other leading SUSY parameters) can be traded against the measured value of M-h. One would be then essentially left with only two free parameters to describe the Higgs sector, tan beta and the pseudoscalar Higgs mass M-A, even at higher orders. The main phenomenological consequence of these high M-S values is to reopen the low tan beta region, tan beta less than or similar to 3-5, which was for a long time buried under the LEP constraint on the lightest h mass when a low SUSY scale was assumed. We show that, in this case, the heavier MSSM neutral H/A and charged H+/- states can be searched for in a variety of interesting final states such as decays into gauge and lighter Higgs bosons (in pairs on in mixed states) and decays into heavy top quarks. Examples of sensitivity on the [tan beta, M-A] parameter space at the LHC in these channels are given.