On the Limits of Chiral Perturbation Theory

Abstract

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 ${\Lambda }_{\chi }$.

Comments: 13 pages, Latex, YCTP-P41-92; we have clarified some of the discussions, the conclusions are unchanged