Precise measurements att=0 of the KLp→KSp amplitude (modulus and phase) were made. Over 50000 Kπ2 decays along with normalizing Kμ3 events were detected behind a 7.2-m-long liquid-hydrogen regenerator. The momentum dependence of the modulus and phase are presented, and the results are combined with those of other experiments to extract the relevant parameters of ω exchange.
RESULTS USING ETA+- = 2.15E-3.
RESULTS USING ETA+- = 2.27E-3.
We have determined the coherent KS regeneration amplitudes on various nuclei, from 20 to 140 GeV/c, using a particularly systematics-free technique. Our results are well represented by |(f−f¯)k|=2.23A0.758p−0.614 mb. This p dependence corresponds to an effective "nuclear" intercept ``αω(0)''=0.386±0.009, whereas the elementary value is αω(0)=0.44±0.01. Comparisons are made with data below 25 GeV/c, and with optical-model predictions. The latter work only if "αω(0)" is postulated to hold for the elementary amplitudes.
No description provided.
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.
No description provided.
No description provided.
No description provided.
The cross sections for the line-reversed reaction pairs K+n→K0p and K−p→K¯0n, and K+p→K0Δ++ and K−n→K¯0Δ− have been determined with high statistics and good relative normalization at 8.36 and 12.8 GeV/c in a spectrometer experiment at Stanford Linear Accelerator Center. The cross sections for the K+-induced reactions are larger than for the K−, contrary to the expectations of weakly-exchange-degenerate Regge-pole models. The ratio of the reaction cross sections is about the same as at lower energies and shows little change with momentum transfer.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
A measurement of the coherent regeneration amplitude in carbon in the energy range 30-130 GeV is presented. The results are consistent with the dominance of this process by ω exchange, and a precise value of the intercept of the ω trajectory is obtained: αω(0)=0.390±0.014.
No description provided.
Differential cross sections for the reactions K−p→K¯0n, K−p→K¯0Δ0, and K+p→K0Δ++ in the region 0<|t|<1.2 GeV2 are presented from a wire-spark-chamber spectrometer experiment performed in a 13-GeV/c separated beam. The results are based on 20 000 Δ++ events, 4600 Δ0 events, and 8500 n events. The line-reversed pair of Δ reactions is used to test Regge exchange degeneracy and an SU(3) sum rule. The energy dependence of all three reactions is studied by comparison with other experiments.
No description provided.
TMIN IS SO MUCH LESS THAN THE RESOLUTION THAT TP DOES NOT DIFFER SIGNIFICANTLY FROM T.
The momentum transfer (t′) dependence of the JP=1+K*π and ρK partial waves in the K±π+π− system is presented. The production of the Q1 meson (m∼1300 MeV), which has a large ρK decay mode, obeys approximate s-channel helicity conservation. In contrast the production of the Q2 meson (m∼1400 MeV), which decays predominantly to K*π, satisfies approximate t-channel helicity conservation. Furthermore the Q1 production distributions are virtually identical, whereas the Q2± distributions exhibit a distinct cross-over for |t′|∼0.18 GeV2.
No description provided.
The differential cross sections and density matrix elements for the φ and ϱ 0 mesons have been measured in the reactions K − p → K − K + ( Λ , Σ 0 ) and K − p → π − π + ( Λ , Σ 0 ) at 13 GeV using a wire chamber spectrometer. The analysis shows that while the vector meson production is dominated by the natural parity exchange amplitude, some unnatural parity exchange is also required. Furthermore the φ and ϱ natural exchange cross sections are identical in shape and have the 2:1 relative strength expected in the quark model with K ∗ and K ∗∗ exchange degeneracy. The analysis of the clear peak-dip ϱ 0 − ω interference pattern observed in the π − π + data indicates that the ω production is in phase with the ϱ and of similar magnitude. Both the S ∗ and f′ meson are clearly observed in this experiment. The S ∗ data are found to be consistent with S ∗ parameters deduced from ππ scattering analyses. The f′ density matrix elements and a new limit of the f′ → π − π + branching ratio are presented.
No description provided.
CROSS SECTIONS CORRECTED FOR EVENTS OUTSIDE THE PHI MASS CUT. <T-CHANNEL>.
CROSS SECTIONS CORRECTED FOR EVENTS OUTSIDE THE PHI MASS CUT. <S-CHANNEL>.
The results of a wire chamber spectrometer experiment studying K ∗ (890) production in the reaction K − p→ K − π + n at 13 GeV are presented. Strong forward structure is observed for | t |< m 2 π in the s -channel density matrix elements and differential cross section. These features are similar to those observed in π − p→ϱ 0 n data and are characteristics of π exchange. In contrast in the intermediate, | t | ∼ 0.2 GeV 2 , and large momentum transfer regions K ∗ (890) production is demonstrated by the natural parity ϱ−A 2 exchange contribution.
No description provided.
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.
No description provided.
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