Effective chiral Lagrangian from $SU(\infty)$ quantum chromodynamics

A nonlinear chiral Lagrangian, which includes an anomalous Wess–Zumino interaction and a mass term describing splitting of the singlet and the nonsinglet meson, is obtained as the low-energy approximation of QCD at large $N$. This is achieved by making, in the functional integral, a change of variables that determines the degrees of freedom responsible for the breaking of the chiral symmetry and corresponding to pseudosealar mesons.