  The axion is a hypothetical elementary particle postulated by the
Peccei-Quinn theory to resolve the strong CP problem in QCD. If axions exist
and have low mass, they are a candidate for dark matter as well. So far our
knowledge of the properties of the QCD axion rests on semi-classical arguments
and effective theory. In this work we perform, for the first time, a fully
dynamical investigation of the Peccei-Quinn theory, focussing on the axion
mass, by simulating the theory on the lattice. The results of the simulation
are found to be in conflict with present axion phenomenology.

High Energy Physics - Lattice;High Energy Physics - Phenomenology;High Energy Physics - Theory;Nuclear Theory