Relaxion dark matter from stochastic misalignment

Cosmological relaxation of the electroweak scale via Higgs-axion interplay, named as relaxion mechanism, provides a dynamical solution to Higgs mass hierarchy. In original proposal by Graham, Kaplan and Rajendran, abundance today is too small explain dark matter universe because high suppression misalignment angle after inflation. It was then realised Banerjee, Kim Perez that reheating effects can displace relaxion, thus enabling it account for from mechanism. However, this scenario in limited region parameter space avoid runaway. We show regime where inflationary fluctuations dominate over classical slow-roll, "stochastic misalignment" field due be large. study evolution inflation, including high-temperature scenario, which barriers potential shrink destabilise temporarily local minimum. open new regions naturally observed density universe, towards larger coupling, mass, mixing angle, smaller decay constant, well