On the detectability of the CMSSM light Higgs boson at the Tevatron

We examine the prospects of detecting the light Higgs boson h0 of the Constrained MSSM at the Tevatron. To this end we explore the CMSSM parameter space with μ > 0, using a Markov Chain Monte Carlo technique, and apply all relevant collider and cosmological constraints including their uncertainties, as well as those of the Standard Model parameters. Taking 50 GeV < m1/2, m0 < 4 TeV, vertical bar A0 vertical bar < 7 TeV and 2 < tan β < 62 as flat priors and using the formalism of Bayesian statistics we find that the 68% posterior probability region for the h0 mass lies between 115.4 GeV and 120.4 GeV. Otherwise, h0 is very similar to the Standard Model Higgs boson. Nevertheless, we point out some enhancements in its couplings to bottom and tau pairs, ranging from a few per cent in most of the CMSSM parameter space, up to several per cent in the favored region of tan β ∼ 50 and the pseudoscalar Higgs mass of mA ∼< 1 TeV. We also find that the other Higgs bosons are typically heavier, although not necessarily much heavier. For values of h0 mass within the 95% probability range as determined by our analysis, a 95% CL exclusion limit can be set with about 2 fb-1 of integrated luminosity per experiment, or else with 4 fb-1 (12 fb-1) a 3σ evidence (5σ discovery) will be guaranteed. We also emphasize that the alternative statistical measure of the mean quality-of-fit favors a somewhat lower Higgs mass range; this implies even more optimistic prospects for the CMSSM light Higgs search than the more conservative Bayesian approach. In conclusion, for the above CMSSM parameter ranges, especially m0, either some evidence will be found at the Tevatron for the light Higgs boson or, at a high confidence level, the CMSSM will be ruled out