Dispersion-Theoretical Fitting of Nucleon-Nucleon Scattering

Abstract

A general approach based on partial-wave dispersion relations is presented for obtaining a formula for phase shifts which depends on only a small number of parameters. This approach does not make any specific assumptions on, or approximations of, the unphysical discontinuity, and involves only approximations of functions that are already known from the general framework of the theory. The method approximately reproduces the ${}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ state in the 0- to 100-Mev range, with two parameters determined from the low-energy data and a third from a phase shift at a higher energy.