Limits of chiral perturbation theory

We consider the relation between the breakdown scale of chiral perturbation theory, ${\Lambda }_{\chi }$, for large values of $N$ (flavor), and the scale associated with "new" physical thresholds. This question is addressed using both the linear $\sigma$ model and an asymptotically free gauge theory to describe the high-energy dynamics. It is suggested that the massive physical threshold could be well above ${\Lambda }_{\chi }$.