SPIN-FLAVOR SYMMETRY AND CONTRACTIONS TOWARDS CLASSICAL SPACE-TIME SYMMETRY

A classification scheme of hadrons is proposed on the basis of the div ision algebra H of quaternions and an appropriate geometry. This schem e suggests strongly to understand flavour symmetry in another manner t han from standard symmetry schemes. In our approach, we do not start f rom ''exact'' symmetry groups like SU(2)xSU(2) chiral symmetry and imp ose various symmetry breaking mechanisms which collide with theorems w ellknown from quantum field theory. On the contrary, the approximate s ymmetry properties of the hadron spectrum at low energies, usually cla ssified by ''appropriately'' broken compact flavour groups, emerge ver y naturally as a low energy reduction of the noncompact (dynamical) sy mmetry group Sl(2,H). This quaternionic approach not only avoids most of the wellknown conceptual problems of Chiral Dynamics but it also al lows for a general treatment of relativistic flavour symmetries as wel l as it yields a direct connection towards classical relativistic symm etry.