Fermion singlet dark matter in a pseudoscalar dark matter portal

We explore a simple extension to the Standard Model containing two gauge singlets: a Dirac fermion and a real pseudoscalar. In some regions of the parameter space both singlets are stable without the necessity of additional symmetries, then becoming a possible two-component dark matter model. We study the relic abundance production via freeze-out, with the latter determined by annihilations, conversions and semi-annihilations. Experimental constraints from invisible Higgs decay, dark matter relic abundance and direct/indirect detection are studied. We found three viable regions of the parameter space, and the model is sensitive to indirect searches.

Automated summary

The model extends the Standard Model by including two gauge singlets, potentially forming a two-component dark matter model. The study focuses on relic abundance production via freeze-out and experimental constraints from invisible Higgs decay, dark matter relic abundance, and direct/indirect detection. Three viable regions of the parameter space were identified, with the model being sensitive to indirect searches.