Two-and four-prong final states in a 28.5-GeV/c p-p bubble-chamber experiment were examined for single-isobar production in various decay channels; results are compared with missing-mass-spectrometer data. The 1400 enhancement was found to be an Nir system with the ratio nir + /pTt 0 ~ 2, which establishes the isospin assignment /= i. The final state A ++ (1238)w was measured and compared with low-energy data to show that the cross section decreases according to ^*Xab~ °* 08 ' consistent with single-pion exchange.

No abstract

No abstract

No abstract

A new high-resolution (±5 MeV) missing-mass spectrometer was used to search for minor peaks and structure in the N* spectrum with ~10 5 events per 2-MeV mass bin. All the widths were found to be narrower than widths obtained from irp phase-shift analyses. For example, our result for W*(1512) is T = 88±2 MeV as compared with the "table value" of 105-155 MeV. No narrow structure greater than 5% of the cross section for the known peaks was observed.