2025/04/05 by Alessio Belfiglio, Orlando Luongo, Belfiglio, Alessio +1 · 3 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.2504.04219
openalex publication_date 2025/04/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the gravitational particle production from vacuum for a minimally coupled fermionic spectator field during a single-field inflationary phase. We observe that metric perturbations arising from the quantum fluctuations of a scalar inflaton field enhance gravitational production, showing that such a perturbative contribution becomes dominant if the field mass is sufficiently smaller than the inflationary Hubble rate. We focus on modes that leave the Hubble horizon during the latest stages of slow-roll and we numerically compute the total number of particles obtained from perturbations, providing a lower bound on the amount of such \enquotegeometric particles for the case of Starobinsky inflation and a quadratic hilltop scenario. Our outcomes are compatible with the net observational cold dark matter abundance as experimentally measured, whose dark matter candidate exhibits mass in the range 105 \lesssim m \lesssim 107 GeV, excluded by previous non-perturbative calculations.