2018/03/31 by Peter Adshead, Lauren Pearce, Marco Peloso +2 · 2 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Fermion #Galaxies: Formation, Evolution, Phenomena #Inflation (cosmology) #Inflaton #Particle physics #Phenomenology (philosophy) #Physics #Pseudoscalar #Quantum electrodynamics #Quark #Scalar (mathematics) #Theoretical physics #astro-ph.CO #hep-ph
paper · pdf · doi:10.1088/1475-7516/2018/06/020
published as JCAP {\bf 1806}, no. 06, 020 (2018) · 48 pages, 9 figures, minor changes, matches published version; v3: added one subsection on spectral index, improved constraints leading to larger parameter space in figure 5, and minor changes
openalex publication_date 2018/06/11 · arxiv created 2019/11/14 · arxiv updated 2019/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.