We show that a gauge singlet scalar S, with a coupling to the Higgs doublet of the form λSS†SH†H and with the S mass entirely generated by the Higgs expectation value, has a thermally generated relic density ΩS≈0.3 if mS≈(2.9–10.5) (ΩS/0.3)1/5(h/0.7)2/5 MeV. Remarkably, this is very similar to the range [mS = (6.6–15.4)η2/3 MeV] required in order for the self-interaction (η/4) (S†S)2 to account for self-interacting dark matter when η is not much smaller than 1. The corresponding coupling is λS≈(2.7×10-10–3.6×10-9) (ΩS/0.3)2/5(h/0.7)4/5, implying that such scalars are very weakly coupled to the standard model sector.
Development of the author's pioneering minimal model for cold dark matter (Gauge singlet scalars as cold dark matter, Phys.Rev. D50 3637). Predicts 1-10 MeV scalar particles which can account for self-interacting dark matter. These have since become a possible explanation for the 511 MeV gamma-ray line observed by INTEGRAL. RAE_import_type : Journal article RAE_uoa_type : Physics
