Cross sections, differential cross sections, and hyperon polarization results are presented for the reactions K¯0p→Λπ+ and K¯0p→Σ0π+ in the momentum interval 1 to 12 GeV/c. Emphasis is placed on the comparison of Λ and Σ channels, and on the momentum dependences of the data. In particular, the Λ polarization data are consistent with being independent of energy above 2 GeV/c; and the slopes of the forward cross sections are found to increase toward the slope values for the line-reversed reactions πp→K(Λ,Σ) as energy increases.
No description provided.
The differential cross sections for KL0p→KS0p scattering are presented in several momentum intervals between 1 and 10 GeVc. The data are strongly peaked in the forward direction, characteristic of a large s-channel helicity-nonflip scattering amplitude in this reaction, and a distinct break in the differential cross section occurs at |t|=0.3 GeV2. The phase of the forward scattering amplitude, φ, is consistent with being independent of momentum. The average value of the phase, φ=−133.9±4.0∘, corresponds to a Regge trajectory α(0)=0.49±0.05 in agreement with the canonical ρ, ω0 Regge intercept, α(0)∼0.5. However, this result disagrees with the Regge trajectory determined from the energy dependence of the forward cross section, α(0)=0.30±0.03, indicating a breaking of the Regge phase-energy relation. Comparisons of KL0p→KS0p and π−p→π0n scattering data reveal substantial differences in the energy dependence of the differential cross sections. Comparisons to KN charge-exchange data then suggest that direct-channel (absorption) effects may explain the differences in πN and KN channels.
DETERMINED FOR COS(THETA) = -0.2 TO 0.2.
Results on the channels K − p → Λ 0 η 0 , Λ 0 π 0 , Σ 0 π 0 , Λ 0 π 0 π 0 and Σ 0 π 0 π 0 are obtained in a K − p formation experiment using 1 million photographs taken in a heavy liquid bubble chamber filled with a CF 3 BrC 3 H 8 mixture. The results are compared with hydrogen bubble chamber (HBC) experiments and with experiments having full or partial gamma-ray detection. Our Λ 0 π 0 and Λ 0 + neutral cross section agree with HBC results. Our Σ 0 π 0 cross section does not exhibit a bump at 1670 MeV as previously seen in HBC experiments. Our Λ 0 π 0 π 0 data are dominated by a Σ (1385) π 0 production. Our Σ 0 π 0 π 0 data is consistent with the presence of some Σ (1405) π 0 production.
No description provided.
The reaction π−+p→Λ+K0 in the 72-in. hydrogen chamber was used to produce 7220 K0 mesons associated with a visible decay Λ→p+π−. The time dependence and absolute yield of the subsequent strong interactions of K0 and K0 in hydrogen were used to determine all the parameters of the neutral K system, without the assumption of CPT invariance or other assumptions about the weak interactions of neutral K's. From the time distribution of 59 events of the type K¯0+p→hyperon, we find the magnitude of the KS0−KL0 mass difference. We then determine the mixing parameters p, q, p′, q′ of the neutral K system by means of the time dependence and absolute yield of 11 charge-exchange events, K0+p→K++n, and the absolute yield of 49 two-body interactions, K¯0+p→hyperon+pion. The results are consistent with CPT invariance and with values of the mixing parameters determined by means of weak interactions. We find the Biswas ratio R≡σ(KLp→KSp)σ(KLp→hyperon) to be R=0.41±0.13 averaged over KL momenta from about 200 to 600 MeVc. This agrees with solution I of Kim and with the results of Kadyk et al. Our absolute yields for K¯0+p→hyperon+pion are in good agreement with the predictions of charge independence and the measured rates for K−+p→hyperon+pion. For the front-back asymmetry of the Λ in K¯0+p→Λ+π+, we find (F−B)(F+B)=−0.48±0.18, indicating that the P wave cannot be neglected relative to the S wave in our momentum range.
TOTAL NUMBER EVENTS=22.
The differential and channel cross sections have been measured for the reactions K L 0 p → K S 0 p and K L 0 p → Λ 0 π + in nine energy intervals in the c.m. range 1605 to 1910 MeV. The regeneration reaction is a combination of the KN amplitudes (with I = 0 and 1) and the K N amplitude ( I = 1) and is very sensitive to the various KN phase-shift solutions, some of which show an exotic I = 0, P 1 resonance. Our results have been expressed in terms of frequency distributions and cross sections, normalised by the Λ 0 π + reaction. These results have been compared with the predictions of various partial-wave analyses. Qualitatively we can eliminate the P 1 non-resonant solution, though no solution correctly predicts our results.
INTEGRATED CROSS SECTION, FORWARD DIFFERENTIAL CROSS SECTION AND CALCULATED PHASE OF THE FORWARD REGENERATION AMPLITUDE. SIG INCLUDES A 4.9 PCT RELATIVE ERROR AS WELL AS EXTRAPOLATION AND STATISTICAL ERRORS.
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