A Chiral Effective Field Theory and Radiative Decays of Mesons

An extended $U(3)_L\bigotimes U(3)_R$ chiral effective field theory which includes pseudoscalar and vector meson nonets as dynamic variables is presented. The theory combines a hidden symmetry approach with a general procedure of including the $\eta'$ meson into chiral theory, and accounts for $direct$ and $indirect$ symmetry breaking effects via a mechanism based on the quark mass matrix. The theory is applied to anomalous radiative decays using particle mixing schemes, corresponding to different symmetry breaking assumptions and uniquely determined by the lagarngian presumed. Radiative decays of light flavor mesons are best explained within the framework of a one mixing angle scheme and provide evidence for $SU(3)_F$ and nonet symmetry breaking.