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arXiv · 2406.09045

Pseudo-Nambu-Goldstone Boson Production from Inflaton Coupling during Reheating

Kunio Kaneta·Sung Mook Lee·Kin-ya Oda·Tomo Takahashi
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Abstract

The existence of pseudo-Nambu-Goldstone boson (pNGB) fields is a common feature in many models beyond the Standard Model, characterized by their exclusive derivative couplings. This paper investigates a scenario where a pNGB is coupled to the inflaton field during the reheating phase of the early universe. We calculate the perturbative decay rate of a coherently oscillating inflaton into pNGBs on a general basis, considering both constant and field-dependent couplings with monomial potentials at the minimum. As a concrete application, we explore the production of axions when the radial mode of the Peccei-Quinn (PQ) scalar serves as the inflaton, particularly in the presence of a large gravitational non-minimal coupling. Our findings suggest that the presence of pNGBs during reheating can lead to significant non-thermal relics, offering new constraints on inflationary reheating models and providing potential observational signatures in the form of dark radiation.

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Kunio Kaneta, Sung Mook Lee, Kin-ya Oda, Tomo Takahashi. 2024-06-13. Pseudo-Nambu-Goldstone Boson Production from Inflaton Coupling during Reheating. https://arxiv.org/abs/2406.09045

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