Chiral bag models and theπN→ππNreaction

Abstract

We explore alternative formulations of bag models preserving chiral symmetry, in which the pion is treated as a separate local field that is allowed to penetrate into the bag interior. Particular emphasis is placed on the cubic terms in the pion field. These are essential for a description of the process $\pi N\to \pi \pi N$. We find that the phenomenology of that reaction indicates a clear preference amongst various possible formulations of chiral bag models with pion penetration of the bag.