Cosmological phase transitions, gravitational waves and self-interacting dark matter in the singlet extension of MSSM

Abstract In the minimal supersymmetric standard model (MSSM) extended by a singlet Custom Shape Photo Light Box superfield, when the coupling between the singlet sector and the MSSM sector is tiny, the singlet sector can be a quasi dark sector with supersymmetry (SUSY).We investigate the cosmological phenomena in this scenario and obtain the following observations: (i) In the parameter space solving the small cosmological scale anomalies via self-interacting singlino dark matter (SIDM), a first-order phase transition (FOPT) can readily happen but requires rather light dark matter below MeV; (ii) The corresponding parameter space indicated by FOPT and SIDM can be partially covered by detecting the phase-transition gravitational waves (GWs) at the near-future projects, link such as LISA, TianQin and Taiji.Therefore, the recently developed GW astronomy could be a novel probe to such a SUSY scenario.