Gravitational wave trispectrum in the axion-SU(2) model. Issue 1 (4th January 2022)

• Record Type: Journal Article
• Authors: Fujita, Tomohiro; Murai, Kai; Obata, Ippei; Shiraishi, Maresuke
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2022:Issue 1(2022)
• Publication Date: 2022-01-04
• Subjects: inflation -- physics of the early universe -- gravitational waves / theory; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2022/01/007
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: We study the trispectrum of the gravitational waves (GWs) generated through the dynamics of an axionic spectator field and SU(2) gauge fields during inflation. In non-Abelian gauge theory, the gauge fields have four-point self-interactions, which induce the tree-level GW trispectrum. We formulate this type of the GW trispectrum including the non-dynamical contributions and evaluate it in the equilateral limit as a unique signal of this model. We find that the ratio of the GW trispectrum to the cube of the scalar power spectrum can be as large as 𝒪(10 6 ) in the viable parameter space, which could be captured in the CMB observations.