Speaker
Description
Speaker: Raymond Co
Abstract: We propose a framework in which the QCD axion simultaneously accounts for the baryon asymmetry and contributes to dark matter through its early-universe rotation. A Peccei–Quinn (PQ) field rotation corresponds to a conserved PQ charge, which can be transferred to baryon number via sphaleron processes (axiogenesis) and to the axion abundance through its kinetic energy (the kinetic misalignment mechanism). However, a rotating axion field that generates the observed baryon asymmetry via axiogenesis typically overproduces axion dark matter via kinetic misalignment. We present a model in which this excess abundance is reduced by interactions with dark magnetic monopoles. We show that monopole-axion couplings induce transitions between dyonic levels that efficiently dissipate the axion’s kinetic energy into dark fermions. The resulting cosmology features a multi-component dark matter sector consisting of axions, monopoles, and dark fermions with comparable energy densities. The viable parameter space requires an axion decay constant below ~10^9 GeV.