Spontaneous CP violation and quark mass ambiguities

Abstract

I explore the regions of quark masses where CP will be spontaneously broken in the strong interactions. The boundaries of these regions are controlled by the chiral anomaly, which manifests itself in ambiguities in the definition of non-degenerate quark masses. In particular, the concept of a single massless quark is ill defined.

Comments: 9 pages, 5 figures, contribution to the 6th Conference on Quark Confinement and the Hadron Spectrum