Invariant background field method for chiral lagrangians including Wess-Zumino terms

Abstract

A chiral invariant background field method is introduced in order to study the structure of higher order terms in chiral perturbation theory. Explicit one-loop calculations are presented together with the construction of the most general O(p6) chiral lagrangian relevant for anomalous processes. The non-renormalization of the coefficient of the Wess-Zumino term in both two and four dimensions is discussed in general. (0 1991 Academic PIN. I~C.

Anomalous chiral perturbation theory meson Lagrangian to orderp6reexamined

“…which has already been used in a slightly different form by several authors (see, e.g., [10,11]). Here, u is defined via u 2 ≡ U.…”

γγ → πππ to one loop in chiral perturbation theory

“…[9,12,15]. We have explicitly checked that the divergences appearing in the one-loop calculation cancel with the known counterterms from the previous references.…”

Chiral perturbation theory for η→π0γγ

“…In [29] it was explicitly shown that the cancellation of the divergences appearing in one-loop diagrams contributing to the process P → γγ * (where P stands for a neutral pseudoscalar meson and γ * is an off mass shell photon) requires the introduction of counterterms. The O(p 6 ) lagrangian contributing to anomalous processes and the coefficients needed to cancel all the divergences are known [31,32,33]. The number of terms in the lagrangian is again very large to determine them experimentally.…”