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 → sγ decay, the cosmological relic density Ω_χh², and the recent measurement of gμ - 2. We normalize products of the expected CMSSM Higgs production cross sections and decay branching ratios σ × β relative to those expected for a Standard Model Higgs boson of the same mass. In the h → γγ channel, we find that [σ(gg → h) × β(h → γγ)]_CMSSM ≳ 0.85 × [σ(gg → h) × β(h → γγ)]_SM. In the W^±/t̄t + h, h → b̄b channels, we find that [σ(W^±/t̄t + h) × β(h → b̄b)]_CMSSM ∼ 1.05 × [σ(W^±/t̄t + h) × β(h → b̄b)]_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^-1 of luminosity at the Tevatron or 10 fb^-1 of luminosity at the LHC.