Bound states of WIMP dark matter in Higgs-portal models. Part II. Thermal decoupling

• Main Authors: Ruben Oncala, Kalliopi Petraki
• Format: Article
• Language: English
• Published: SpringerOpen 2021-08-01
• Series: Journal of High Energy Physics
• Subjects: Beyond Standard Model; Cosmology of Theories beyond the SM
• Online Access: https://doi.org/10.1007/JHEP08(2021)069

Abstract The Higgs doublet can mediate a long-range interaction between multi-TeV particles coupled to the Weak interactions of the Standard Model, while its emission can lead to very rapid bound-state formation processes and bound-to-bound transitions. Using the rates calculated in a companion paper, here we compute the thermal decoupling of multi-TeV WIMP dark matter coupled to the Higgs, and show that the formation of metastable dark matter bound states via Higgs-doublet emission and their decay decrease the relic density very significantly. This in turn implies that WIMP dark matter may be much heavier than previously anticipated, or conversely that for a given mass, the dark matter couplings to the Higgs may be much lower than previously predicted, thereby altering the dark matter phenomenology. While we focus on a minimal singlet-doublet model in the coannihilation regime, our calculations can be extended to larger multiplets where the effects under consideration are expected to be even more significant.