QUARK MODELS IN N(N)OVER-BAR ANNIHILATION AT LOW ENERGIES

Models for internal annihilation of quarks as a mechanism for baryon-a ntibaryon (B1BBAR2) production at low energy ppBAR scattering are disc ussed. The results in form of branching ratios for different B1BBAR2 c hannels are compared with existing data either at a fixed center of ma ss energy square-roots or at the same excess energy epsilon = square-r oots - m(B1) - m(B2). We find reasonable agreement with experimental d ata provided the internal quark interaction is of vector type. These r esults are contrasted to qqBAR annihilation proceeding via an effectiv e instanton interaction or in the context of Nambu-Jona-Lasinio type o f models.