Abstract :
We discuss the mass spectrum of highly-excited nucleon and Δ∗ resonances. The spectrum exhibits parity doublets, pairs of resonances of identical total angular momentum J but of opposite parity. It has been proposed that the parity doublets evidence restoration of chiral symmetry at large baryon excitation energies. We compare this conjecture with the possibility that high-mass states are organized into (L,S)-multiplets with defined intrinsic quark spins and orbital angular momenta. The latter interpretation results in a better description of the data. There is however a small trend possibly indicating the onset of chiral symmetry restoration.
