Effective Action for Composite Operators and Chiral Symmetry Breakdown in Asymptotically Free and Non-Asymptotically Free Gauge Theories.

摘要

An essential distinction in the realization of the PCAC dynamics in asymptotically free and non-asymptotically free (with a non-trivial ultraviolet-stable fixed point) gauge theories is revealed. For the latter theories, an analytical expressions for the condensate is obtained in the two-loop approximation and arguments of support of a soft behaviour at small distances of composite operators are given. The problem of factorizing the low-energy region for the Wess-Zumino-Witten action is discussed. Besides, the mass relations for pseudoscalar mesons in arbitrary THETA-sector are obtained in the first order in fermion bare masses and the impossibility for spontaneous P and CP-symmetries breaking in vector-like gauge theories at THETA=0 is shown. 20 refs. (Atomindex citation 19:065295)