Results are presented on effective-mass distributions, differentisl cross sections and longitudinal c.m. momentum distributions for the channels K − p → K − p π o , K o p π − and K − π + n , obtained from a sample of approximately 28 000 inelastic two-pronged interactions at 4.2 GeV/ c incident momentum. The results are in satisfactory agreement with the prediction of a generalized Veneziano-model corrected for (non-dual) π -and pomeron exchange. For the channel K − pπ o pomeron exchange contributes about 20% of the cross section. In the channel K − π + n the dual, pion and pomeron contributions are responsible for resp. 15%, 65% and 20% of the total cross section.
BREIT-WIGNER FITS.
MEASURED OFF GRAPH.
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We present results of an analysis of two-prong events for elastic scattering and single-pion production in K−p interactions at 5.5 GeVc. The resonance parameters for the charged and neutral K*(890) and K*(1420) are determined and the observed production and decay properties of the charged and neutral K*(890) are compared with the theoretical predictions of an absorptive one-particle-exchange model and a Regge model. The K*(1420) differential cross section and density-matrix elements are presented and the question of whether more than one resonance exists in this mass range is considered. A search for resonance effects at Kπ mass beyond 1500 MeV is made. In particular, the recently reported state at 1800 MeV is discussed. A B5-model analysis of the reaction K−p→K¯0π−p is also presented.
NORMALIZED TO SIG(K- P --> ANYTHING) OF 24.3 +- 0.8 MB.
FORWARD CROSS SECTION OPTICAL POINT FROM TWO PARAMETER EXPONENTIAL FIT OVER 0.12 < -T < 0.68 GEV**2.
No description provided.
Differential cross sections and density matrix elements are presented for K ∗− (890) and K ∗− (1400) produced in the reaction K − p→K O π − p at 3.95 GeV/ c . The cross sections are decomposed into contributions due to different exchange mechanisms.
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The reaction K − p → X K − p has been measured at 25 and 40 GeV/ c at the Serpukhov accelerator using the CERN-IHEP boson spectrometer. At both energies we observe production of the resonances K ∗− (890) and K ∗− (1420) in the channels K ∗− → K 0 π − and K − π 0 ; the momentum dependence of their production cross sections is found to be σ[ K ∗− (890)] ∞ p inc −1.48±0.04 and σ [ K ∗− (1420)] ∞ p inc −0.8±0.2 .
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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).
The K π − system produced in the reaction K p → K 0 π − p at 4.2 GeV/ c is studied using high-statistics bubble-chamber data. The spin-parity structure is analysed as a function of the K 0 π − mass up to 1.52 GeV. Production of K ∗ (890) and K ∗ (1420) is observed in helicity-0 and helicity-1 states. Contributions of natural and unnatural parity exchange are present. Considerable S-wave production is observed over the whole mass region considered. We also study the t ′ dependence of the K ∗ (890) and K ∗ (1420) amplitudes. A comparison of our results on K ∗ (890) production with the results of an analysis of charge-exchange K ∗ (890) production, allows the separation of I = 0 and I = 1 exchange amplitudes. Some qualitative remarks are made concerning K ∗ (1420) production.
No description provided.
PARTIAL WAVE ANALYSIS ASSUMING SPIN-COHERENCE TO OBTAIN SPIN-PARITY STRUCTURE AND T DEPENDENCE OF P-WAVE AND D-WAVE AMPLITUDES.
We present a systematic investigation of channel cross sections in K − p interactions at 32 GeV/ c . The energy dependence of these cross sections is discussed. We also investigate a few non-diffractive two-body reactions. The total cross sections of the two reactions K − p → K ∗− (890) p and K − p → K ∗− (1420) p have a markedly different energy behaviour. There is clear evidence for the reaction K − p → K ∗0 (890) N 0 (1688) ; its differnttial cross section exhibits a sharp forward slope of 24 ± 3 GeV −2 .
FROM AK0 P PI- FINAL STATE.
DOUBLE RESONANCE CHANNEL CROSS SECTIONS FROM BREIT-WIGNER FIT CORRECTED FOR BACKGROUND AND DIFFRACTIVE PROCESSES.
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Mesons decaying into π 0 or η and one charged meson were studied using a liquid-argon calorimeter in a non-magnetic double-arm spectrometer. Cross sections and energy dependences are presented. The ϱ ± production mechanisms are discussed in detail: ω and π exchange contribute the largest fractions, but also A 2 exchange is present. ϱ ± production by ω exchange is shown to follow the energy behaviour predicted by the Regge trajectory α ω ( t ) = 0.4 − | t |.
Axis error includes +- 0.0/0.0 contribution (13 TO 25////STATISTICAL ERRORS ARE SMALLER THAN THE SYSTEMATIC ERRORS).
No description provided.
Data from the ANL 12-foot bubble chamber have been used to study the K¯0π− system in the reaction K−p→K¯0pπ− at 6.5 GeV/c. Signals for the production of K*(892), K*(1430), and K*(1780) were observed with cross sections of 181±22, 41.2±6, and 8.4±2.9 ≥b, respectively. The partial waves contributing to the production of the K¯0π− system from threshold up to 1.7 GeV were studied. The principal conclusions are: (i) K*(892) and K*(1430) production is dominated by natural-parity exchange, (ii) the ratio of unnatural- to natural-parity exchange increases with the resonance mass, consistent with the predictions of a triple-Regge model, (iii) there is evidence for a broad 0+ s-wave enhancement, with considerable s−d and s−p interference, centered at 1.2 GeV, and (iv) the m=2 amplitudes are negligible.
<AK0 PI-> EFFECTIVE-MASS DISTRIBUTION FITTED WITH BREIT-WIGNER FUNCTIONS AND CUBIC POLYNOMIAL BACKGROUND. FITTED MASS OF KN(1800)- IS 1762 +- 9 MEV.
THE LARGE BACKGROUND UNDER THE K*(1420)- IS SUBTRACTED USING A LINEAR FIT.
NOT CORRECTED FOR PRESENCE OF BACKGROUND.
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