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 $\frac{1}{2},\frac{3}{2},\frac{5}{2}$. The scheme also gives selection rules in the one-pion decay: The absence of the parity nonchanging decay $N\left(1720\right)\to \pi \Delta \left(1232\right)$ is a typical example which should be confirmed experimentally to unravel the role of ChS in baryon resonances.