Disappearing inflaton potential via heavy field dynamics

Naoya Kitajima, Fuminobu Takahashi

Research output: Contribution to journalArticle

Abstract

We propose a possibility that the inflaton potential is significantly modified after inflation due to heavy field dynamics. During inflation such a heavy scalar field may be stabilized at a value deviated from the low-energy minimum. In extreme cases, the inflaton potential vanishes and the inflaton becomes almost massless at some time after inflation. Such transition of the inflaton potential has interesting implications for primordial density perturbations, reheating, creation of unwanted relics, dark radiation, and experimental search for light degrees of freedom. To be concrete, we consider a chaotic inflation in supergravity where the inflaton mass parameter is promoted to a modulus field, finding that the inflaton becomes stable after the transition and contributes to dark matter. Another example is a hilltop inflation (also called new inflation) by the MSSM Higgs field which acquires a large expectation value just after inflation, but it returns to the origin after the transition and finally rolls down to the electroweak vacuum. Interestingly, the smallness of the electroweak scale compared to the Planck scale is directly related to the flatness of the inflaton potential.

Original languageEnglish
Article number041
JournalJournal of Cosmology and Astroparticle Physics
Volume2016
Issue number2
DOIs
Publication statusPublished - 2016 Feb 17

Keywords

  • inflation
  • particle physics - cosmology connection
  • physics of the early universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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