HEP Theory Journal Club

The Flavor of QCD axion dark matter

Gonzalo Alonso-Alvarez

McGill

There exists a whole landscape of QCD axion models. However, if this particle is to make up the dark matter, the absence of catastrophic domain walls and exotic strongly interacting relics singles out two minimal versions of hadronic axions as the only viable possibilities. I argue that these models generically predict sizeable flavor-violating axion couplings to quarks that can be probed at terrestrial rare meson decay experiments. In particular, kaon decay experiments like NA62 and KOTO are sensitive to QCD axions with masses down to 10 μeV, well into the mass region where the QCD axion can make up the whole dark matter abundance via the standard post-inflationary misalignment mechanism.