Radius of the Nucleon in a Bound-State Model

Abstract

We estimate the nucleon radius from the pion-nucleon phase shifts, assuming that the nucleon is a bound state of the pion and the nucleon. The calculation is based on the one-pole approximation of the Gelfand-Levitan formalism on the inverse scattering problem. The numerical result of 0.15-0.50 F is obtained for the radius. In this connection, we discuss the properties of the phase shift and also of the $D$ function for the appropriate channel.