The reaction T-9 + qn has been observed through the decay mode 7 -t 27 a t T,-=592, 653, 704, 875, 975, 1117, and 1300 MeV. The detection apparatus was a cubic array of six steel-plate optical spark chambers that completely surrounded a liquid-hydrogen target. We identified events attributed to the decay of an 7 by the large c.m. opening angle between the two showers generated in the steel plates by the decay photons. We have calculated the total cross section for 7 production, which is proportional to the number of events under the large-angle peak in the opening-angle distribution. The total cross section rises steeply from threshold to a maximum of about 2.4 mb a t 650 MeV, and then falls gradually to about 0.66 mb a t 1300 MeV. The differential cross section was obtained by taking the coefficients of a Legendre-polynomial fit to the angular distribution of bisectors of selected two-shower events, and converting them to the coefficients of the 7 c.m. angular distribution. The differential cross section is found to be isotropic a t 592 MeV, to require terms through Pe(cos0,) between 655 and 975 MeV, and to have a forward peak fitted by terms through P~(CO&,) a t 1117 MeV and through P.%(CO&~) a t 1300 MeV. I t is suggested that production a t threshold is predominantly through an S state, with some PI and Da waves entering by 655 MeV.We suggest that all the absorption in the Sli T N state can be explained by the 7 production.
In this paper we use new data from several recent KN experiments in conjunction with older data to make an energy-dependent partial-wave analysis of the KN system. The important new additions never used before in a partial-wave analysis are our precision measurements of the charge-exchange total cross sections, our ,measurements of the charge-exchange angular distributions, and the first measurements of the K p polarization at these low momenta. A new feature introduced in the analysis is the S-wave cusp treatment at the Ag and Zoq thresholds, which we find necessary to describe the observed behavior in the chargeexchange total cross sections near these thresholds. Other features include a single-channel unitary formulation for resonances and backgrounds and a parametrization of these amplitudes incorporating centrifugal-barrier effects. New values for masses, widths, and elasticities for resonances in this region are reported and better evidence is found for several of the less well established resonances. None of the new resonances suggested by recent I = 0 and I = 1 total-cross-section measurements are required. Fits are displayed for all the data used and predictions of this partial-wave analysis are compared with those of two other recent analyses for certain quantities yet to be measured. A table of the amplitudes, in steps of 20 MeV/c, is provided.
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