Dark Matter and Baryogenesis from Visible-Sector Long-Lived Particles

• Published in: arXiv.org
• Main Authors: Allahverdi, Rouzbeh, Ngo Phuc Duc Loc, Osiński, Jacek K
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 16.06.2023
• Subjects: Antiparticles; Baryons; Cosmology; Dark matter; Fermions; Physics - Cosmology and Nongalactic Astrophysics; Physics - High Energy Physics - Phenomenology; Physics - High Energy Physics - Theory; Radiation; Standard model (particle physics); Universe
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2212.11303

We present a minimal extension of the standard model that includes a long-lived fermion with weak-scale mass and an \({\cal O}({\rm GeV})\) fermionic dark matter candidate both of which are coupled to quarks. Decays of a TeV-scale colored scalar in a radiation-dominated phase bring the former to a thermal abundance while also producing dark matter. The long-lived fermion then dominates the energy density of the Universe and drives a period of early matter domination. It decays to reheat the Universe, mainly through baryon-number-violating interactions that also generate a baryon asymmetry, with a small branching fraction to dark matter. We find the allowed parameter space of the model and show that it can be probed by proposed long-lived particle searches as well as next-generation neutron-antineutron oscillation experiments. This model provides a robust explanation of dark matter and baryogenesis as long as the Universe is in a radiation-dominated phase at \(T \gtrsim {\cal O}({\rm TeV})\).