$\pi-N$ from an Extended Effective Field Theory

Abstract

Third order chiral perturbation theory accounts for the $\pi-N$ scattering phase shift data out to energies slightly below the position of the $\Delta$ resonance. The low energy constants are not accurately determined. Explicit inclusion of the $\Delta$ field is favored.Comment: 2 pages latex, working group talk, Chiral Dynamics 2000, Jefferson Lab., VA, July 2000, World Scientific, to be pu