Theory Colloquium

# The QCD Axion: A Candidate for Dark Matter?

## by Gerrit Schierholz (DESY)

Wednesday, November 14, 2018 from to (Europe/Berlin)
at DESY Hamburg ( build. 2a, SR2 )
 Description 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 a fully dynamical investigation of the Peccei-Quinn theory, focussing on the impact of QCD on key axion parameters, by simulating the PQWW/DFSZ action on the lattice. The results of the simulation, including the axion mass and effective potential, are found to be in contradiction with current axion phenomenology and question the validity and use of the Peccei-Quinn theory.