Quark mass uncertainties revive Kim-Shifman-Vainshtein-Zakharov axion dark matter

Abstract

The Kaplan-Manohar ambiguity in light quark masses allows for a larger uncertainty in the ratio of up to down quark masses than naive estimates from the chiral Lagrangian would indicate. We show that it allows for a relaxation of experimental bounds on the quantum chromodynamics axion; specifically Kim-Shifman-Vainshtein-Zakharov axions in the 2-3νeV mass range composing 100% of the galactic dark matter halo can evade the experimental limits placed by the ADMX collaboration. © IOP Publishing Ltd.