Exploration of the MSSM with non-universal Higgs masses

We explore the parameter space of the minimal supersymmetric extension of the Standard Model (MSSM), allowing the soft supersymmetry-breaking masses of the Higgs multiplets, m ₁ , ₂ , to be non-universal (NUHM). Compared with the constrained MSSM(CMSSM) in which m ₁ , ₂ are required to be equal to the soft supersymmetry-breaking masses m ₀ of the squark and slepton masses, the Higgs mixing parameter μ and the pseudoscalar Higgs mass m _A , which are calculated in the CMSSM, are free in the NUHM model. We incorporate accelerator and dark matter constraints in determining allowed regions of the (μ,m _A ), (μ,M ₂ ) and (m ₁ /2,m ₀ ) planes for selected choices of the other NUHM parameters. In the examples studied, we find that the LSP mass cannot be reduced far below its limit in the CMSSM,whereas m _A may be as small as allowed by LEP for large tan β. We present in Appendices A-D details of the calculations of neutralino-slepton, chargino-slepton and neutralino-sneutrino coannihilation needed in our exploration of the NUHM.