Phenomenological Lagrangians and the light mesons

A phenomenological Lagrangian describing the light pseudoscalar mesons is constructed, including strong, electromagnetic, and weak interactions. Limitations of the method, especially for non-leptonic weak interactions, are considered. The proper method of renormalizing the theory is discussed. One loop corrections to the Gell-Mann-Okubo formula and the f/sub K/f/sub π/ ratio are computed. Also, the problem of defining the theory of a phenomenological Lagrangian involving multiple derivative terms is resolved. The solution is that any measure for the path integral which is invariant under the symmetries can be ued