Maximal temperature of strongly-coupled dark sectors
Publisher DOI
Abstract
Taking axion inflation as an example, we estimate the maximal temperature (Tmax) that can be reached in the post-inflationary universe, as a function of the confinement scale of a non-Abelian dark sector (ΛIR). Below a certain threshold ΛIR < Λ0 ∼ 2 × 10−8mpl, the system heats up to Tmax ∼ Λ0 > Tc, and a first-order thermal phase transition takes place. On the other hand, if ΛIR > Λ0, then Tmax ∼ ΛIR < Tc: very high temperatures can be reached, but there is no phase transition. If the inflaton thermalizes during heating-up (which we find to be unlikely), or if the plasma includes light degrees of freedom, then heat capacity and entropy density are larger, and Tmax is lowered towards Λ0. The heating-up dynamics generates a gravitational wave background. Its contribution to Neff at GHz frequencies, the presence of a monotonic ∼ shape at (10−4 – 102) Hz frequencies, and the frequency domain of peaked features that may originate via first-order phase transitions, are discussed.
Date Issued
2023-05-31
Publication Type
Article
Subject(s)
Language(s)
en
Author(s)
Journal
Journal of High Energy Physics
Publisher
Springer
ISSN
1029-8479
Access(Rights)
open.access