Dilution of dark matter relic density in singlet extension models

• Published in: The journal of high energy physics Vol. 2023; no. 2; pp. 8 - 24
• Main Authors: Xiao, Yang, Yang, Jin Min, Zhang, Yang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2023; Springer Nature B.V; SpringerOpen
• Subjects: Classical and Quantum Gravitation; Dark matter; Density; Dilution; Electroweak model; Elementary Particles; High energy physics; Lower bounds; Models for Dark Matter; Nucleation; Phase transitions; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Specific BSM Phenomenology; String Theory; Transition temperature; Upper bounds; Models for Dark Matter; Specific BSM Phenomenology
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP02(2023)008

A bstract We study the dilution of dark matter (DM) relic density caused by the electroweak first-order phase transition (FOPT) in the singlet extension models, including the singlet extension of the standard model (xSM), of the two-Higgs-doublet model (2HDM+S) and the next-to-minimal supersymmetric standard model (NMSSM). We find that in these models the entropy released by the strong electroweak FOPT can dilute the DM density to 1/3 at most. Nevertheless, in the xSM and NMSSM where the singlet field configure is relevant to the phase transition temperature, the strong FOPT always happens before the DM freeze-out, making the dilution effect negligible for the current DM density. We derive an analytical upper bound on the freeze-out temperature and a numerical lower bound on nucleation temperature in the xSM. On the other hand, in the 2HDM+S where the DM freeze-out temperature is independent of FOPT, the dilution may salvage some parameter space excluded by excessive DM relic density or by DM direct detections.