In an experiment at the CERN intersecting storage rings with √ s = 31 GeV, we have measured αP , the product of asymmetry parameter and polarization, for Λ 0 's and Λ 0 's produced in p p and pp interactions, respectively. The ratio, (αP) Λ /(αP Λ = −1.04±0.29 , is consistent with the value −1, and constitutes the first test of CP invariance in Λ decay.
The ratio CONST/CONST is obtained under assumption of POL(LAMBDA) = POL(LAMBDABAR).
Exclusive ϱ 0 production has been measured in 120, 200 and 280 GeV muon-proton interactions at high Q 2 (1 GeV 2 < Q 2 < 25 GeV 2 ) and W (6 GeV < W < 19 GeV). The photoproduction cross section decreases as 1/ Q 4 . A shallow t distribution, typical of a hard scattering process is observed and the ϱ 0 is found to be dominantly in the helicity zero spin state. The ϱ 0 s are mainly produced by transverse photons and s -channel helicity conservation seems to be invalid. The data cannot be described by the vector meson dominance model. These data show that at high Q 2 even exclusive ϱ 0 muoproduction is a hard scattering process and that the soft hadron-like properties of the photon have disappeared.
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SYSTEMATIC ERROR ON SLOPE IN 0.8.
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SECOND REACTION CORRESPONDS TO COLLISIONS OF VARIOUS NUCLEAR PAIRS (C C, C NE, O NE, C CU, C ZR, C PB, O PB), FOR DETAILS SEE: ZP C25, 1. PLAB = 3.7 GEV/A|.
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Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
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Results onK0 and Λ production ine+e− annihilation at c.m. energies of 14, 22 and 34 GeV are presented. The shape of theK0 and Λ differential cross sections are very similar to each other and to those of π±,K± and\(p(\bar p)\). Scaling violations are observed forK0 production. We obtain a value for the probability to produce strange quark-antiquark pairs relative to that to produce up or down quark-antiquark pairs of 0.35±0.02±0.05. The value ofRh=σ(e+e-→hX)/σµµ is shown to rise steadily with c.m. energy for all particle species. At 34 GeV we find 1.48±0.05K0 and 0.31±0.03 Λ per event. We have searched for possible Λ polarization. The production ofK0's and Λ's in jets is examined as a function ofpT2 and rapidity and compared to that of all charged particles; the yields in two and three jets are also investigated. Results are presented from events with two baryons\((\Lambda ,\bar \Lambda ,por\bar p)\) observed.
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Measurements are reported of the difference ΔσL between proton-proton total cross sections for parallel and antiparallel spin states and of the parameter CLL for proton-proton elastic scattering near 90°, for thirteen energies between 300 and 800 MeV. The ΔσL results agree well with previous ANL ZGS and SIN data, but disagree with recent results from TRIUMF. Attempts to understand the cause of the discrepancy have been unsuccessful, but possible sources are discussed. The ΔσL and CLL results have been used with other experimental data to extract quantities which depend only on spin-singlet, coupled spin-triplet, and spin-triplet partial waves. Structure is found in these quantities, which appears to be associated with the resonantlike D21 and F33 partial waves. Additional similar structure is also found, which may be due either to the P03 partial wave or the (P23,F23) partial-wave pair.
ERROR IS STATISTICAL ONLY (ERROR IN BRACKETS IS STATISTICAL WITH THE ENERGY DEPENDENT UNCERTAINTIES FOLDED IN).
ERRORS ARE STATISTICAL ONLY. THERE IS ADDITION OF 2.0 AND 2.1 PCT SYSTEMATICS.
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The depolarization parameter D NN for pp elastic scattering at θ cm = 90 ° has been measured at twelve momenta between 0.9 and 1.5 GeV/ c . The moduli of the three transversity amplitudes T 1 , T 3 , and T 4 have been extracted from these data and from previous measurements of the differential cross section and spin correlation parameter A NN (90 °). Smooth energy dependence is found for all three amplitude moduli.
Axis error includes +- 3/3 contribution (DUE TO UNCERTAINTIES IN THE TARGET ANALYSING POWER).
Measurements of C LL of pp elastic scattering near θ c.m. = 90° at thirteen energies between 300 and 800 MeV are reported. These, together with previous values of C NN , are used to extract values of two quantities, ƒ s and ƒ t , which contain only spin-singlet and only coupled spin-triplet partial waves, respectively. The ƒ s curve, which is not dependent on C LL , exhibits the behavior expected for the previously conjectured 1 D 2 resonance. The ƒ t curve also exhibits a resonance-like behavior, which could be due either to the 3 P 0 or the 3 P 2 partial wave.
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