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arXiv · 2109.06457

Gravitational wave trispectrum in the axion-SU(2) model

Tomohiro Fujita·Kai Murai·Ippei Obata·Maresuke Shiraishi
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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 $\mathcal{O}(10^6)$ in the viable parameter space, which could be captured in the CMB observations.

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Tomohiro Fujita, Kai Murai, Ippei Obata, Maresuke Shiraishi. 2021-09-14. Gravitational wave trispectrum in the axion-SU(2) model. https://doi.org/10.1088/1475-7516/2022/01/007

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