Observability of the Lightest CMSSM Higgs Boson at Hadron Colliders

We discuss the observability of the lightest neutral Higgs boson in the constrained MSSM (CMSSM), with universal soft supersymmetry-breaking parameters, at hadron colliders such as the Tevatron and the LHC. We take account of the constraints on parameter space provided by LEP, the measured rate of b to s gamma decay, the cosmological relic density Omega h^2, and the recent measurement of g_mu - 2. We normalize products of the expected CMSSM Higgs production cross sections and decay branching ratios (sigma B)_CMSSM relative to those expected for a Standard Model Higgs boson of the same mass. In the h to gamma gamma channel, we find that (sigma B)_CMSSM > 0.85 (sigma B)_SM. In the W/t tbar + h, h to b bbar channels, we find that (sigma B)_CMSSM \~ 1.05 (sigma B)_SM. We conclude that the lightest CMSSM Higgs boson should be almost as easy to see as the Standard Model Higgs boson: in particular, it should be discoverable with about 15/fb of luminosity at the Tevatron or 10/fb of luminosity at the LHC.