Chiral-symmetry realization for even- and odd-parity baryon resonances
Baryon resonances with even and odd parity are collectively investigated from the viewpoint of chiral symmetry (ChS). We propose a quartet scheme where Delta's and N(*)'s with even and odd parity form a chiral multiplet. This scheme gives parameter-free constraints on the baryon masses in the quartet, which are consistent with observed masses with spin 1 / 2,3 / 2,5 / 2. The scheme also gives selection rules in the one-pion decay: The absence of the parity nonchanging decay N(1720)-->piDelta(1232) is a typical example which should be confirmed experimentally to unravel the role of ChS in baryon resonances.
Jido
D
Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
Hatsuda
T
Kunihiro
T