Experimental results on the K L 0 p → K S 0 p reaction at 11 laboratory momenta between 300 and 800 MeV/ c are presented. The data are used to discriminate among the various sets of phase shifts for K + N scattering in the I = 0 state.
STATISTICAL ERRORS ONLY. CROSS SECTIONS ARE NORMALIZED RELATIVE TO THE PI+ LAMBDA EVENTS - SEE THE RECORD OF L. BERTANZA ET AL., NP B110, 1 (1976).
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We present a comparative study of inclusive and semi-inclusive pion production in pp collisions at 102 and 400 GeV/ c . In particular, we examine the correlation between transverse and longitudinal momentum variables and the energy dependence of invariant cross sections.
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The reactions e + d → e ' + p S + p + π − and e + d → e ' + n S + n + π + were measured detecting electron and pion in coincidence at an invariant hadronic mass of 2.19 GeV. The measurements were performed at electron four-momentum transfer squared of f 2 = 0.70 and 1.35 GeV 2 in the range of t = ( γ v − π ) 2 between t min and −1.0 GeV 2 . The cross section d 2 σ / dtdφ of the reaction e + n → e' + p + π − was determined.
ACTUALLY RATIO OF PI- TO PI+ PRODUCTION OFF DEUTERIUM.
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The production of multipion events by e + e − annihilation has been measured at centre of mass energies 915,990 and 1076 MeV. Both channels e + e − → π + π − π o and e + e − → π + π − π + π − have been analysed. An energy threshold effect analysed. An energy threshold effect around 919 MeV ( m ω + m π o ) has been evidenced for the π + π − π o π o channel and the cross section is consistent with the quasi two-body process e + e − → ωπ o . The cross section for π + π − π + π − is lower by an order of magnitude and increases with the energy.
SYSTEMATIC ERROR INCLUDED. RADIATIVE EFFECT (<15 PCT) INCLUDED.
MULTIHADRON PRODUCTION CROSS SECTION DEDUCED AS SUM OF FOUR PION CHANNELS.
An analysis of the Kπ-system in the mass region of the K ∗ (1780), based on a sample of 46000 K s o π + final states, is presented. Evidence for a relatively narrow width, τ ≈ 100 MeV, and for the spin parity assignment J P = 3 − is found.
SLOPE DETERMINED WITHIN 0.2 < -T < 0.8 GEV**2 AND USED TO ESTIMATE TOTAL CROSS SECTION.
A partial wave analysis of the K 0 π + π − system produced in the charge exchange reaction K − p → ( K 0 π + π − ) n at 4.2 GeV/ c has been performed both as a function of Kππ mass and of t ′. The 1 + S wave forms the largest contribution to the K ππ system and peaks at roughly the same mass as the Q in diffractive K ππ production. The polarization properties of the 1 + S ( K ∗ π) and 1 + S (Kϱ) waves differ fromt those of the diffractive 1 + wave. There is some evidence for a resonance contribution to 1 + S ( K ∗ π) . The strong 2 + wave the K ∗ (1420) and the K ϱ/ K ∗ ϱ decay branching ratio determined to be 0.36±0.10. An enhancement with spin-parity 1 − is observed under K ∗ (1420) .
CROSS SECTION CORRECTED FOR BREIT-WIGNER TAILS, THE TP CUT, UNSEEN <AK0 PI> AND <K RHO> DECAY MODES. BRANCHING RATIO K*(1420) --> <K RHO>/<K* PI> = 0.36 +- 0.10.
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Elastic scattering of 32.1 GeV/ c K + on protons has been measured in a bubble chamber experiment. Results are presented in the momentum transfer interval 0.06–1.40 GeV 2 and compared with data at different energies. An effective Regge trajectory is calculated using K + p elastic data from 10 to 175 GeV/ c .
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Measurements of the polarised beam asymmetry parameter Σ for eta photoproduction from protons, have been carried out at incident energies of 2.5 GeV and 3.0 GeV, and for various t -values between −0.2 (GeV/c) 2 and −1.2 (GeV/c) 2 . The values of Σ are close to +1 for values of | t | less than 0.7 (GeV/c) 2 , showing that there can be little contribution from unnatural parity exchange in any Regge exchange model of the process, in disagreement with present theories. Differential cross sections for the process werre also measured, and are consistent with those from other experiments.
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The Λ p total cross section has been measured in the Λ momentum range 4–14 GeV/c. The weighted mean of the cross section over this momentum interval is σ( Λ p) = 49.3 ± 3.7 mb for an average Λ momentum of 8.3 ± 2.7 GeV/ c . This value differs from the corresponding value for σ(Λp) measured previously by 14.5 ± 3.8 mb. Assuming a variation with Λ momentum, pΛ , of the form σ( Λ p) − σ(Λp) = σ 1pΛ − 1 2 , a value of σ 1 = 47 ± 10 mb GeV − 1 2 is obtained.
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The reaction π + p→ ωΔ ++ (1236) is studied at 16 GeV/ c . Cross section, differential cross section, single and joint spin-density matrix elements are given and the correlations between the ε and Δ ++ (1236) decay angular distributions are investigated. Natural and unnatural spin-parity exchanges contribute to this reaction in roughly equal amounts. Natural exchanges lead predominantly to Δ ++ (1236) with helicity ± 3 2 , while unnatural exchanges lead predominantly to Δ ++ (1236) with helicity ± 1 2 and to ε with helicity zero. Furthermore, unnatural exchanges are small at t ′≅0.2 GeV 2 compared to other t ′ values, which may be due to the nonsense wrong-signature-zero of the B-meson exchange. Quark model relations are found to be satisfied by the data.
CORRECTED FOR UNSEEN OMEGA DECAY MODES. 'SLICE METHOD' USED TO HANDLE RESONANCE TAILS AND BACKGROUND.
FROM EVENTS WITHIN MASS-CUTS FOR RESONANCES AND NORMALIZED TO TOTAL CROSS SECTION.
'ALL'.
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