Chiral Symmetry Realization for Even- and Odd-parity Baryon Resonances

Abstract

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 non-changing decay N(1720) -> pi Delta(1232) is a typical example which should be confirmed experimentally to unravel the role of ChS in baryon resonances.