Dark matter production via a non-minimal coupling to gravity

• Published in: Journal of cosmology and astroparticle physics 2023-02, Vol.2023 (2), p.35
• Main Authors: Lebedev, Oleg, Solomko, Timofey, Yoon, Jong-Hyun
• Format: Article
• Language: English
• Subjects: Astrophysics; Couplings; Dark matter; dark matter simulations; dark matter theory; General Relativity and Quantum Cosmology; High Energy Physics - Phenomenology; Physics; physics of the early universe
• ISSN: 1475-7516; 1475-7508; 1475-7516
• DOI: 10.1088/1475-7516/2023/02/035

We study postinflationary scalar dark matter production via its non-minimal coupling to gravity. During the inflaton oscillation epoch, dark matter is produced resonantly for a sufficiently large non-minimal coupling ξ ≳ 5. We find that backreaction on the curvature and rescattering effects typically become important for the values of ξ above 30, which invalidate simple estimates of the production efficiency. At large couplings, the dark matter yield becomes almost independent of  ξ , signifying approximate quasi-equilibrium in the inflaton-dark matter system. Although the analysis gets complicated by the presence of apparent negative energy in the Jordan frame, this behaviour can be regularized by introducing mild dark matter self-interaction. Using lattice simulations, we delineate parameter space leading to the correct dark matter relic abundance.