Gravitational waves and dark matter from classical scale invariance

In this paper we consider a minimal classically conformal U(1) model of fermionic dark matter. We calculate the one loop effective potential which generates the mass scale quantum mechanically via dimensional transmutation in the spirit of Gildener and Weinberg, and examine the effects of the new dark sector on the Standard Model Higgs as well as how the dark fermions receive a mass and can produce the observed relic abundance. We then consider constraints on the model coming from collider and direct detection experiments before calculating the thermal effects on the potential in the early Universe. We examine the nature and conditions for a strongly first-order phase transition in our model and calculate the associated gravitational wave signal and compare to the sensitivities of current and proposed experiments.