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AVERAGED DATA FOR 44.9 AND 45.5 GEV.
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Results on inclusive K s 0 production in e + e − annihilation at mean center-of-mass energies of 9.4, 12.0 and 30 GeV are presented. The ratio R (K 0 ) = 2 σ (K s 0 )/ σ μμ rises from 3.10 ± 0.75 at √ s = 9.4 GeV to 5.6 ± 1.2 at √ s = 30 GeV, corresponding to an approximately constant K 0 /charged-particle ratio of 0.12 ± 0.02. A similar ratio for K 0 / charged particle is observed for direct hadronic decays of the ϒ.
SYSTEMATIC ERROR INCLUDED.
NUMBER OF K0 PER HADRONIC EVENT. AUTHORS ALSO USE MULTIPLICITY TO ESTIMATE NUMBER OF K0 PER CHARGED PARTICLE.
INCLUDING EARLIER DATA.
Inclusive coherent proton diffraction dissociation on helium has been measured in the four-momentum transfer and missing-mass region 0.04<|t|<0.40 (GeV/c)2, MX2<10 GeV2 and for incident proton beam momenta from 46 to 400 GeV/c. We find that the differential cross section d2σdtdMX2 varies slowly with energy, reveals a pronounced peak at MX2≃2 GeV2, and at large masses behaves approximately as 1MX2. The cross section falls exponentially as |t| increases, with a large slope parameter at small momentum transfers and a substantially smaller one at large |t| values, with no clear dip between the two regions as seen in elastic scattering. We compare the experimental t distributions to Glauber-model predictions and find the data provide a sensitive test of the assumptions on the details of the elementary proton diffraction-dissociation amplitudes and on the total cross sections of the diffractively produced states.
No description provided.
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AVERAGED DATA FOR 200 AND 259 GEV.
Data on hadron production by e + e − annihilation at c.m. energies between 12 and 36.6 GeV have been collected using the JADE detector. They have been analysed in terms of single-photon and weak neutral-current exchange assuming production of quark-antiquark pairs with only d, u, s, c and b quarks to produce values for the quark weak neutral-current couplings. A further analysis in terms of the Glashow-Salam-Weinberg theory produced the result, sin 2 θ W = 0.22 ± 0.08 . The theory has therefore been tested in a new energy domain and within the context of the neutral weak couplings of the first, second and third generation quarks.
No description provided.
WIDTH(Z) = 2.5 GEV WAS ASSUMED. CONST(N=SIN2TW) WAS DETERMINED FROM RATIO(HADRONS/MU). FIRST ORDER QCD.
Measurements of the reaction γ p → p π + π − π + π − are presented, in which π + π − π + π − systems with masses up to 3 GeV are produced from fragmentation of the incident photon. The reaction is dominated by production of the large peak of the ϱ′(1600) meson and, at higher masses ≳2 GeV, y production of jet-like 4 π systems. The ϱ′(1600) meson is produced by a predominantly s -channel helicity conserving mechanism. At higher masses there are also indications of ϱπ peaks, of masses 1.3 GeV (the A 2 meson) and 1.75 GeV, produced with a recoiling π meson by a mechanism consistent with the Deck effect.
CORRECTED FOR TAILS OF BREIT-WIGNER RESONANCE USED IN FIT AND ALLOWING FOR 10 PCT BACKGROUND.
We have measured the reaction ee → μμ and ee → ττ at center of mass energies from 9.4 to 31.6 GeV. The production cross sections are in agreement with the predictions of quantum electrodynamics, resulting in cutoff parameter limits of 70–100 GeV at 95% c.l. The branching ratio for τ → μν ν has been determined as [1.78 ± 2.0 (statist.) ± 1.8(syst.)]% The existence of a new sequential heavy lepton with a mass <14.5 GeV is excluded at 95% c.l.
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The polarization of 26 000 Σ+ hyperons produced by 400-GeV protons on Be has been measured. The polarizations of Σ+ and Λ hyperons have the opposite sign. The magnitude increases with momentum at 5-mrad production angle, and averages 22% over the momentum range 140 to 280 GeV/c.
No description provided.
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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.
We have measured the polarization for elastic scattering in the reaction π−p→π−p at 2.93 and 3.25 GeV/c using a polarized proton target and multiwire proportional chambers (MWPC's) with emphasis on large-angle scattering. Events were selected by fast scintillation-counter logic. Beam trajectories were measured with four MWPC's and the scattered-particle angles were measured with one or two MWPC's; elastic events were determined by coplanarity and angle-angle correlations. The polarization is in agreement with previous measurements below |t|=2.0 (GeV/c)2, and crosses from negative to positive near the secondary dip in the differential cross section dσdt. In the backward region, an energy dependence appears with the polarization being large and negative at 2.93 GeV/c and consistent with zero at 3.25 GeV/c.
No description provided.
No description provided.
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