Quark masses, chiral symmetry, and the U(1) anomaly

Abstract

I discuss the mass parameters appearing in the gauge theory of the strong interactions, concentrating on the two flavor case. I show how the effect of the CP violating parameter $\theta$ is simply interpreted in terms of the state of the æther via an effective potential for meson fields. For degenerate flavors I show that a first order phase transition is expected at $\theta =\pi .$ I speculate on the implications of this structure for Wilson's lattice fermions.

Comments: 12 pages, 9 figures, uses sprocl.sty. Talk at conference "Quark confinement and the hadron spectrum," Como, June 1996