P-wave excited baryons from pion- and photo-induced hyperon production

We report evidence for $N(1710)P_{11}$, $N(1875)P_{11}$, $N(1900)P_{13}$, $Δ(1600)P_{33}$, $Δ(1910)P_{31}$, and $Δ(1920)P_{33}$, and find indications that $N(1900)P_{13}$ might have a companion state at 1970\,MeV. The controversial $Δ(1750)P_{31}$ is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy independent $πN$ scattering amplitudes from either KH84 or GWU. The two $πN$ amplitudes from KH84 or GWU, respectively, lead to slightly different $πN$ branching ratios of contributing resonances but the debated resonances are required in both series of fits.

No reviews yet.

No comments yet.