The $\pi \pi$ scattering amplitude in chiral perturbation theory

Abstract

We discuss $\pi \pi$ scattering in the framework of chiral perturbation theory. In particular, we recall the predictions made some time ago for the threshold parameters and for the phase shift difference ${\delta }_0^0-{\delta }_1^1$.

6 pages, LaTex, uses epsf.tex and epsfig.sty; 2 uufiled figures included. To be published in the second edition of the DA$\Phi$NE Physics Handbook, eds. L. Maiani, G. Pancheri and N. Paver (to appear)