Axiogenesis with a heavy QCD axion

We demonstrate that the observed cosmological excess of matter over anti-matter may originate from a heavy QCD axion that solves the strong CP problem but has a mass much larger than that given by the Standard Model QCD strong dynamics. We investigate a rotation of the heavy QCD axion in field space, which is transferred into a baryon asymmetry through weak and strong sphaleron processes. This provides a strong cosmological motivation for heavy QCD axions, which are of high experimental interest. The viable parameter space has an axion mass m_a between 1 MeV and 10 GeV and a decay constant f_a< 10⁵ GeV, which can be probed by accelerator-based direct axion searches and observations of the cosmic microwave background.