Filtered pseudo-scalar dark matter and gravitational waves from first order phase transition

Abstract If dark matter (DM) acquires mass during a first order phase transition, there will be filtering-out effect when DM enters the expanding bubble. In this paper we study for pseudo-scalar DM, whose may partially come from transition in hidden sector. We calculate ratio of that enter bubble various wall velocities as well status (in thermal equilibrium, or out equilibrium) at time which results small penetration rate affect final relic abundance DM. further stochastic gravitational wave signals emitted by sector space-based interferometer experiments smoking-gun model.