Effective action for composite operators and chiral-symmetry breaking in asymptotically free and asymptotically nonfree gauge theories
It is shown that in the local limit the condition that the effective action of composite operators be independent of the parameters of chiral rotations (a condition that guarantees the spontaneous character of the breaking of the chiral symmetry) imposes extra restrictions (in addition to the equations of motion) on the Green functions. A substantial difference between the realizations of the chiral dynamics in asymptotically free and asymptotically nonfree (with a nontrivial ultraviolet-stable fixed point) gauge theories is established. For the latter, in the two-loop approximation, an analytical expression is obtained for the condensate and arguments are given in support of ''soft'' behavior of the composite operators at short distances. The problem of distinguishing the low-energy region for the Wess-Zumino-Witten action is discussed. In addition, in first order in the bare masses of the fermions, mass relations for the pseudoscalar mesons in an arbitrary theta-sector are obtained and the impossibility of spontaneous breaking of the P and CP symmetries in vector-like gauge theories with theta = 0 is demonstrated.
- Research Organization:
- Institute of Theoretical Physics, Academy of Sciences of the Ukrainian SSR
- OSTI ID:
- 6968158
- Journal Information:
- Sov. J. Nucl. Phys. (Engl. Transl.); (United States), Vol. 47:2
- Country of Publication:
- United States
- Language:
- English
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