We present a systematic analysis of the production of K ∗+ (892) and Δ ++ (1236) resonances in the K + p → K 0 p π + reaction at 5, 8.25 and 16 GeV/ c . We have measured total cross sections, differential cross sections, density matrix elements and examined resonance production mechanisms in terms of the exchange of states with definite naturality. Some results on the reaction K + p → K ∗+ (1420) p are also given.
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The reactions K + p → K ∗+ (890) p , K + p → K ∗+ (1420) p and K + p → K 0 Δ ++ have been systematically studied for eleven incident momenta between 3.0 and 16.0 GeV/ c . Cross sections, differential cross sections and density matrix elements are presented. For K ∗ (890) production the contributions from natural and unnatural parity exchanges have also been separated into I = 0 and I = 1 components. Effective trajectories have been extracted in the case of natural parity exchange, and also for Δ ++ production.
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DATA AT NEIGHBOURING MOMENTA ARE GROUPED TOGETHER. THE RESONANCE PRODUCTION TOTAL CROSS SECTIONS ARE FITTED BY P**-N. THIS TABLE GIVES THE VALUES FOR EACH GROUP OF MOMENTA OF THE FITTED TOTAL CROSS SECTIONS WHICH ARE USED TO NORMALIZE THE DIFFERENTIAL CROSS SECTIONS.
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Results are given from a study of 15 518 events of the reaction K + d → K + π − pp. The K + π − spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K + π − → K + π − elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier K π scattering studies using the reaction K + p → K + π − Δ ++ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.
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Elastic K+p scattering at a beam momentum of 4.27 GeV/c is studied and compared with elastic K−p scattering in order to extract the imaginary part of the non-Pomeranchukon-exchange amplitude. The single-pion-production cross sections are presented as well as production cross sections and resonance parameters for the Δ(1236), the K*+(890), and the K*+(1420). Production and decay distributions for the Δ++(1236) and the K*+(890) are presented and compared with the absorptive particle-exchange model and with Regge-pole-exchange models.
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BREIT-WIGNERS PLUS PHASE SPACE TO DETERMINE RESONANCE PRODUCTION CROSS SECTIONS.
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We present high-statistics data on differential cross sections and density matrix elements for K*±(890) production obtained in a 13-Gev/c SLAC experiment. The most remarkable features of the data are the dominance of natural-parity exchange and significant differences between K*+ and K*− production by natural-parity isoscalar exchange. We present two exchange models which successfully describe this difference, as well as the overall t dependence: model A including Pomeron plus strongly exchange-degenerate Regge poles and model B involving broken exchange degeneracy for the f and ω exchanges. These two phenomenological models lead to different predictions for the energy dependence of K*± production, for the relative K*(1420)K*(890) production rate, and for the SU(3)-related ρ± production processes.
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High statistics data for the reactions K ± p → K S 0 π ± p at 10 GeV/ c are analysed. The K ∗ (1 − ), K ∗ (2 + ), and K ∗ (3 − ) resonance parameters and production cross sections are calculated. The Kπ production amplitudes are determined as a function of t and the produced Kπ mass. Isoscalar natural-parity-exchange (NPE) is dominant. The t dependence of the K ± NPE amplitudes have a cross-over at t = −0.3 (GeV/ c ) 2 for both K ∗ (890) and K ∗ (1420) production, being more pronounced for the K ∗ (1420). Natural-parity-exchange interference effects are isolated. The NPE amplitudes are decomposed into pomeron-, f-, and ω-exchange contributions. S-wave Kπ production is found to be consistent with the Kπ partial-wave analyses of charge-exchange reactions.
CORRECTED FOR BACKGROUND, BREIT-WIGNER TAILS AND T-ACCEPTANCE. SYSTEMATIC ERROR INCLUDED.
DATA FOR K PI PRODUCTION AND ANGULAR DISTRIBUTIONS ARE IN THE PRECEDING PAPER, R. BALDI ET AL., NP B134, 365 (1978).
Results are presented on an analysis of the reaction K + p → K ∗+ (890) p at 16 GeV/ c and compared with data at lower incident momenta and with corresponding results for the reaction K − p → K ∗− (890) p. It is found for both reactions that the energy dependence of the cross section exhibits a simple ( p − n lab behaviour.
BREIT-WIGNER RESONANCE FITS WITH BACKGROUND.
Data are presented on the production of the KN π final states in K + p interactions at 7.3 GeV/ c . The energy dependence of the KN π final state cross sections, the effective-mass distributions, and the spectra of c.m. longitudinal momenta are given, and features of these data are compared with predictions of the generalized Veneziano (GV) model. Furthermore, we present the momentum transfer and decay angular distributions for K ∗ (890), K ∗ (1420) and Δ (1236) production within the KN π final states and discuss these quasi-two-body reactions in terms of the GV model.
BREIT-WIGNER RESONANCE FITS WITH BACKGROUND CONTRIBUTION.
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We present results on a number of non-diffractive two-body channels contributing to reactions K + p→K 0 π + p and K + p→K + π − π + p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K + beam of 32 GeV/ c at the Serpukhov accelerator. Total cross sections are given for the final states K ∗+ (890) p , K ∗+ (1420) p , K 0 Δ ++ (1232), K ∗+ (890) p , Δ ++ (1232), K ∗0 (1420) Δ ++ (1232), K ∗0 (1780) Δ ++ (1232) and K ∗0 (890) Δ ++ (1950) . The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied.
FROM K0 P PI+ FINAL STATE.
DOUBLE RESONANCE CHANNEL CROSS SECTIONS CORRECTED FOR BACKGROUND, BREIT-WIGNER TAILS AND DIFFRACTIVE PROCESSES.
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A simultaneous partial-wave analysis of the three final states K + p, K ∗ (892)N and KΔ(1236) is attempted using inelastic data with large statistics at 1.21, 1.29, 1.38 and 1.69 GeV/ c as well as existing data on the elastic reaction. The constraint of unitarity, which is almost saturated by these reactions, allows one to determine the size and relative phases of the dominant partial waves and to give some limits on the others. Their variation with energy is discussed, as well as the consistency of the different sets of elastic phase shifts with the inelastic data. We also compare the predictions of the duality hypothesis with the data.
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