Non-thermal Higgs spectrum in reheating epoch: primordial condensate vs. stochastic fluctuation

Since electroweak symmetry is generally broken during inflation, the Standard Model Higgs field can become supermassive even after the end of inflation. In this paper, we study the non-thermal phase space distribution of the Higgs field during reheating, focusing in particular on two different contributions: primordial condensate and stochastic fluctuations. We obtain their analytic formulae, which agree with the previous numerical result. As a possible consequence of the non-thermal Higgs spectrum, we discuss perturbative Higgs decay during reheating for the case it is kinematically allowed. We find that the soft-relativistic and hard spectra are dominant in the decay rate of the stochastic fluctuation and that the primordial condensate and stochastic fluctuations decay almost at the same time.

Automated summary

This paper studies the properties of the Higgs field in the non-thermal phase space distribution after the end of inflation, focusing on the contributions of primordial condensate and stochastic fluctuations, and obtains analytic formulas. The perturbative Higgs decay during reheating is discussed as a possible consequence of the non-thermal Higgs spectrum and it is found that the primordial condensate and stochastic fluctuations decay almost at the same time.