Gravitational wave background from non-Abelian reheating after axion-like inflation. Issue 5 (1st May 2022)

• Record Type: Journal Article
• Authors: Klose, P.; Laine, M.; Procacci, S.
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2022:Issue 5(2022)
• Publication Date: 2022-05-01
• Subjects: particle physics - cosmology connection -- primordial gravitational waves (theory) -- axions -- inflation; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2022/05/021
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: A pseudoscalar inflaton φ, coupled to the topological charge density FF̃ of a non-Abelian sector, can decay to gauge bosons ( φ ⟶ gg ), which may thermalize rapidly. The friction felt by φ is then increased by non-Abelian "strong sphalerons", leading to a self-amplifying process that can efficiently heat up the medium. We determine a lower bound for the gravitational wave production rate from such a process, originating via hydrodynamic fluctuations and particle collisions, in terms of a minimal number of parameters. Only a moderate fraction of energy density is converted to gravitational waves, suggesting that non-Abelian models may avoid the overproduction observed in some Abelian cases.