Lippmann-Schwinger Resonating-Group Formalism for NN and YN Interactions in an SU6 Quark Model

We formulate a Lippmann-Schwinger-type resonating-group equation to calculate invariant amplitudes of the quark-model baryon-baryon interaction. When applied to our recently proposed SU6 quark model for the nucleon-nucleon and hyperon-nucleon interactions, this technique yields very accurate phase-shift parameters for all partial waves up to energies of several GeV. The technique also has the merit of providing a straightforward derivation of the G-matrix equation. A new analytic method is proposed to calculate the quark exchange Born kernel for the momentum-dependent two-body interaction. The partial-wave decomposition in the momentum representation is carried out numerically. The invariant amplitudes are then used to calculate single-nucleon potentials in normal nuclear matter for high incident momenta (q1 ≥ 3f m −1 ), in which the so-called t eff ρ prescription is found to be a good approximation of the single-particle potentials directly calculated in the lowest-order Brueckner theory.