A minimal gauge inflation model**JG was supported in part by the Basic Science Research Program through the National Research Foundation of Korea Research Grant 2016R1D1A1B03930408, a TJ Park Science Fellowship of the POSCO TJ Park Foundation; SCP was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (2016R1A2B2016112)

Abstract

In this paper, we present a gauge inflation model based on the orbifold with non-Abelian SU(2) gauge symmetry, which is probably the simplest model in this category. As the inflaton potential is fully radiatively generated exclusively by gauge self-interactions, the model is predictive; thus, it is protected by gauge symmetry itself, without the introduction of any additional matter fields or arbitrary interactions. We show that the model fully agrees with the recent cosmological observations within the controlled perturbative regime of gauge interactions, g4 ≲ 1/(2πRMP), with the compactification radius (10 ≲ RMP ≲ 100): the expected magnitude of the curvature perturbation power spectrum and the value of the corresponding spectral index are in perfect agreement with the recent observations. The model also predicts a large fraction of the gravitational waves, negligible non-Gaussianity, and a sufficiently high reheating temperature.