The Reaction $\pi N\to \pi \pi N$ at Threshold

Abstract

We consider the chiral expansion for the reaction $\pi N\to \pi \pi N$ in heavy baryon chiral perturbation theory. To order $M_{\pi }$ we derive novel low--energy theorems that compare favorably with recent determinations of the total cross sections for ${\pi }^{+}p\to {\pi }^{+}{\pi }^{+}n$ and ${\pi }^{-}p\to {\pi }^0{\pi }^{0}n$.

Comments: 7 pp, LateX (uses epsf.sty), 3 figures appended as ps files (split off as ppnf1.ps,ppnf2.ps,ppnf3.ps), CRN 94/19