ON THE PARITY DEGENERACY OF BARYONS

The gross features of the observed baryon excitation spectrum below 2 GeV are well explained if the spectrum generating algebra of its intri nsic orbital angular momentum states is o(4) circle times su(2)(I). Th e spins of the resonances are obtained through the coupling of a Loren tz bi-spinor {1/2, 0} circle plus {0, 1/2} to a multiplet of the type {j,j} in its O(4)/O(3) reduction. The parities of the resonances follo w from those of the 0(3) members of the {j,j} multiplets. In this way relativistic SL(2, C) representations are constructed. For example, th e first S-11, P-11, and D-13 states with masses around 1500 MeV fit in to the {1/2, 1/2} circle times [{1/2, 0} circle plus {0, 1/2}] represe ntation. The observed parities of the resonances correspond to natural parities of the {1/2, 1/2} states. The second P-11, S-11, D-13 - toge ther with the first P-13, P-15, D-15, and (a predicted) F-17-resonance s, centered around 1700 MeV, are organized into the {3/2, 3/2} circle times [{1/2, 0} circle plus {0, 1/2}] representation. We argue that th e members of the (3/2, 3/2) multiplet carry unnatural parities and tha t in this region chiral symmetry is restored. In the N(939) --> N(1650 ) transition the chiral symmetry mode is changed, and therefore, a chi ral phase transition is predicted to take place.