Singlino-dominated dark matter in general NMSSM

Abstract

Abstract The general Next-to-Minimal Supersymmetric Standard Model (NMSSM) describes the singlino-dominated dark-matter (DM) property by four independent parameters: singlet-doublet Higgs coupling coefficient λ, Higgsino mass μtot, DM mass $$ {m}_{{\tilde{\chi}}_1^0} $$ m χ ˜ 1 0 , and singlet Higgs self-coupling coefficient κ. The first three parameters strongly influence the DM-nucleon scattering rate, while κ usually affects the scattering only slightly. This characteristic implies that singlet-dominated particles may form a secluded DM sector. Under such a theoretical structure, the DM achieves the correct abundance by annihilating into a pair of singlet-dominated Higgs bosons by adjusting κ’s value. Its scattering with nucleons is suppressed when λv/μtot is small. This speculation is verified by sophisticated scanning of the theory’s parameter space with various experiment constraints considered. In addition, the Bayesian evidence of the general NMSSM and that of Z3-NMSSM is computed. It is found that, at the cost of introducing one additional parameter, the former is approximately 3.3 × 103 times the latter. This result corresponds to Jeffrey’s scale of 8.05 and implies that the considered experiments strongly prefer the general NMSSM to the Z3-NMSSM.