Internal Seminar: Basic Aspects of Dark Matter Production & Axions in the Early Universe

by Frank Steffen (MPI), Peter Graf (MPI)

Thursday 8 Apr 2010, 11:15 → 12:15 Europe/Berlin

313 (Seminar room)

Abstract of the second part: The smallness of the CP violating term in the QCD Lagrangian is the well known strong CP problem. If it is solved via the Peccei-Quinn mechanism, the pseudo-Nambu-Goldstone boson associated with the spontanteous breaking of the new U(1) symmetry is the axion. We study the behaviour of axions in the early Universe and calculate the temperature at which the axion decouples from the early QCD plasma.