Quarks and baryon-baryon scattering. AP-matrix analysis of nucleon-nucleon scattering

We have performed a $P$-matrix analysis of the existing nucleon-nucleon phase-shift analyses. The $P$ matrix accounts for the short-range interactions between the six quarks; its poles correspond to multiquark configurations confined in a bag. It is parametrized with a form that is a modification of the no-scattering $P$ matrix. In this way we obtain a boundary condition on the baryon-baryon scattering wave function. The known long-range baryon-baryon interaction due to pion exchange then enables us to calculate the scattering matrix. Although we have to make several assumptions mainly due to the lack of data, the results are very encouraging and show that a $P$-matrix parametrization of the short-range part of the interaction not only may be a practical way to parametrize the data, but also may yield more information about the interactions between the quarks.