PROPERTIES OF K](890) AND K](1400) PRODUCED IN K-P INTERACTIONS AT 4.1 AND 5.5 GEV/C

The results presented in this paper were obtained from an analysis of K-p interactions in the 30-in. hydrogen bubble chamber at the Argonne ZGS using incident K- beams of momenta 4.1 and 5.5 GeV/c. The K̄πN final states were studied extensively; the most prominent feature of these is production of the K*(890) and K*(1400) resonances. The K̄0π-π+n final state was used to measure the branching ratio of the decay of the K*(1400) into K*(890)π and Kρ. Evidence for quasi-two-body production of K*(890)- and K*(1400)- is presented both from the two-prong events in which the positive track was identified as a proton, and from events where the K̄0 decay was observed. For final states with a missing neutron, a study of the missing-mass distributions proved that the kinematical fits to K-π+n and K̄0π-π+n final states could be used with confidence to study K*(890)0 and K*(1400)0 production. The K*(890)0,- production angular distribution and decay correlations are analyzed in the framework of the absorptive peripheral model. Vector exchange dominates the K*(890)- production, whereas K*(890)0 is formed mainly via pseudoscalar exchange. An absorptive-peripheral-model calculation using the vector-meson coupling strengths to the nucleon given by relativistic SU(6) gives a good fit to the K*(890)0,- density-matrix elements as a function of production angle, and gives a reasonable fit to the differential cross section. For the K*(1400) resonance, a mass and width of 1416±8 and 107±20 MeV are obtained. Decay branching ratios measured for this resonance of Kπ:K*π:Kρ of 1: (0.52±0.12): (0.26±0.16) are in agreement with those predicted from SU(3) assuming the K*(1400) is a member of a 2+ nonet. The absorptive peripheral model gives no reasonable fits to the K*(1400) production angular distributions. The K*(1400)0,- production and decay angular distributions suggest that the spin parity of the K*(1400) is 2+, but without many more events, or a better model for the production mechanism, we cannot make a decisive determination. © 1968 The American Physical Society.