Experimental constraints on the nearly minimal supersymmetric standard model and implications for its phenomenology

We examine various direct and indirect experimental constraints on the nearly minimal supersymmetric standard model (nMSSM) and obtain the following observations: (i) Current experiments stringently constrain the parameter space, setting a range of 1∼37  GeV for the lightest neutralino χ˜₁⁰, 30∼140  GeV (1∼250  GeV) for the lightest CP-even (CP-odd) Higgs boson, and 1.5∼10 for tan⁡β; (ii) To account for the dark matter relic density, besides the s-channel exchange of a Z boson, the s-channel exchange of a light A₁ (the lightest CP-odd Higgs boson) can also play an important role in lightest supersymmetric particle annihilation. Compared with the Z-exchange annihilation channel, the A₁-exchange channel is more favored by muon g-2 data and allows much broader regions for the parameters; (iii) In a large part of the allowed parameter space the SM-like Higgs boson may dominantly decay to χ˜₁⁰χ˜₁⁰ or A₁A₁ and the conventional visible decays (e.g. into bottom quarks) are severely suppressed.