Finite meson-size effects in nucleon-nucleon phase shifts

We use a quark model of the nucleon to determine the interaction between two nucleons. A scalar potential is utilized to confine the quarks and to determine the quark wave function. We include relativistically a pion cloud around the nucleon and use a local pion-quark interaction to determine the energy of the three valence quarks and the pion cloud with parameters chosen to reproduce the pion-nucleon coupling. For a finite pion size the cloud energy is finite. This relativistic pion-cloud energy is added to the non-relativistic energy of the three valence quarks to determine the nucleon mass. A stable nucleon of the right size and mass comes out of this calculation. The form factors for the one-boson-exchange potential are calculated taking finite meson size into account. Pion cloud and valence quarks are included in a resonating group approach for calculating the two-nucleon phase shifts. The 1S0 phase shifts agree well with experiment. The net effect of finite meson size in this model is a slightly smaller phase shift. (orig.)