Mixing Particle Production for Relaxion Mechanism

Abstract

We consider the production of two heavy gauge bosons as a relaxation stopping mechanism. In this work, we analyse the conditions for a tachyonic mode for a linear combination of gauge bosons and show that the criteria are significantly different than the single gauge boson case. Moreover, the implementation of the mechanism on the $U(1)'$ model is demonstrated. We discuss various constraints for the relaxion mechanism. The phenomenology of the heavy gauge boson is also explored. We finally show a benchmark point of parameter space considering all constraints from relaxion and the $U(1)'$ mixing sector.