Unitarity corrections to kaon-pion scattering from current algebra

A method is presented to unitarize the hard-meson current algebra kaon-pion amplitude derived by Ford. Elastic unitarity is satisfied in the lowest-order correction to current algebra. The amplitude contains? three real parameters and does not have any arbitrary function for simulating left-hand discontinuities. Once the isospin-half P-wave is given in the low-energy region, this method leads to a sharp determination of the S-wave phase shifts. Our solution favors the “down” type for the $\text{I =}\text{1}\text{2}$ S-wave phase shifts.