The reaction K+p → KN in all three final charge states at 3 GeV/c

The reaction K+p → KNπ has been studied in all three final charge states at a momentum of the incident K-meson of 2.97 GeV/c. The resonance K*(890) is produced with a cross-section of (1.56±0.19) mb and a decay branching ratio (K* → K+π0)/(K* → K0π=) = 0.43 ± 0.11. The resonanceN*(1236) is produced asN*++ with the cross-section (0.70±0.13) mb and asN*+ with the cross-section (0.27±0.08) mb. The decay branching ratio ofN*+, (N* → nπ+/(N* → pπ0) is 0.05 ± 0.20. The consequences of an interference between states with different isotopic spin of the (Nπ)-system are discussed. The decay correlations of the resonance events are presented and the spin space density matrix elements for the resonances are calculated. TheN* decay distributions agree with the predictions of the model of Stodolsky and Sakurai. The decay angular correlations of the two decay modes of K*, K* → K0π+, and K* → K+π0, are found to be significantly different. This may be explained as due to an interference between states with different isotopic spin of the (Kπ)-system. The K* decay correlations, when interference effects are eliminated, indicate that the resonance is produced to a great extent via the exchange of a vector meson (one-meson exchange model). The production angular distributions of both resonances are sharply peaked. The modified one-particle exchange model of jacksonet al. is shown to give a reasonable account of these distributions as well as of the decay correlations and the variation of the density matrix elements with the production angle of the resonance.