Quarks, few-body systems, and relativity

Before coming to the relativistic aspects of quark dynamics the author wants to comment briefly on two N.R. formulations involving 6q systems, presented at this symposium, one by Erich Schmid, the other by Yeong Kim. Both formulations suggest the potentially powerful role of the RGM for few-cluster systems for an eventually satisfactory multiquark dynamics. By insisting on the orthogonality requirement among the different channel spaces (NN,ΔΔ,CC), he finds that for the chosen (NN) channel the coupling effects of the auxiliary ones (ΔΔ,CC) are small, thus effectively wiping out the node in the NN wave function, hitherto believed to be a signature of the repulsive core. This once again leaves open the question of understanding the latter within the quark dynamics, but the author mentions, here a calculation bearing on this very feature in terms of a QCD-oriented Bag model. Another ''clean'' feature of the formalism is the smallness of the 3-cluster Pauli potential, a result found by Cheng-guang Bao in collaboration with Schmid. But for N.R. premises, the general features of this cluster formalism are microscopic enough to survive an eventual relativistic formulation. The author now comes to the last and most difficult part of the discussion, viz. the inclusion of relativistic effects in the quark dynamics. In view of the unusually light masses of u,d,s, quarks which account for most of our nuclear matter (apart from the rare and exotic ''heavy'' flavoured baryons) it would be futile to treat relativistic effects, as mere corrections in successive powers of (v/c). One needs at minimum a closed form relativistic formulation of the type