Disformal dark matter
Philippe Brax (Institut de Physique théorique, Université Paris-Saclay, CEA, CNRS, F-91191 Gif-sur-Yvette Cedex, France); Kunio Kaneta (School of Physics, Korea Institute for Advanced Study, Seoul 02455, Korea); Yann Mambrini (Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France); Mathias Pierre (Instituto de Física Teórica (IFT) UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain, Departamento de Física Teórica, Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, 28049 Madrid, Spain)
We generalize dark matter production to a two-metric framework whereby the physical metric, which couples to the Standard Model (SM), is conformally and/or disformally related to the metric governing the gravitational dynamics. We show that this setup is naturally present in many Ultra Violet (UV) constructions, from Kähler moduli fields to tensor-portal models, and from emergent gravity to supergravity models. In this setting we study dark matter production in the early Universe resulting from both scatterings off the thermal bath and the radiative decay of the inflaton. We also take into account noninstantaneous reheating effects at the end of inflation. In this context, dark matter emerges from the production of the scalar field mediating the conformal/disformal interactions with the SM, i.e., realizing a Feebly Interacting Matter Particle (FIMP) scenario where the suppression scale of the interaction between the scalar and the SM can be taken almost as high as the Planck scale in the deep UV.