Novel Cosmological Roles and Experimental Searches of (QCD) Axions
Raymond Co (Minnesota U.)

We established a paradigm where the (QCD) axion’s novel cosmological evolution, a rotation in the field space, can give rise to axion dark matter via kinetic misalignment and can generate the observed baryon asymmetry of the Universe via axiogenesis. The axion rotation also leads a kination era, leaving unique signatures in the primordial gravitational wave spectrum. For ultralight (QCD) axions, this cogenesis scenario makes intriguing predictions on axion properties more experimentally accessible than the conventional ones. For heavy and cosmologically unstable QCD axions, the predictions from axiogenesis point to regions that can be probed by neutrino experiments and long-lived particle searches. We will also discuss how the presence of an axion-muon coupling will facilitate such probes at, e.g., ArgoNeuT, DUNE, FASER 2, and SHiP.