Phenomenology of fermion production during axion inflation

Peter Adshead, Lauren Pearce, Marco Peloso, Michael A. Roberts, Lorenzo Sorbo

Research output: Contribution to journalArticlepeer-review


We study the production of fermions through a derivative coupling with a pseudoscalar inflaton and the effects of the produced fermions on the scalar primordial perturbations. We present analytic results for the modification of the scalar power spectrum due to the produced fermions, and we estimate the amplitude of the non-Gaussianities in the equilateral regime. Remarkably, we find a regime where the effect of the fermions gives the dominant contribution to the scalar spectrum while the amplitude of the bispectrum is small and in agreement with observation. We also note the existence of a regime in which the backreaction of the fermions on the evolution of the zero-mode of the inflaton can lead to inflation even if the potential of the inflaton is steep and does not satisfy the slow-roll conditions.

Original languageEnglish (US)
Article number020
JournalJournal of Cosmology and Astroparticle Physics
Issue number6
StatePublished - Jun 11 2018


  • axions
  • cosmological perturbation theory
  • ination
  • non-gaussianity

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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