Decay modes of the charmed mesons, D 0 and D + , are studied in e + e − annihilation data at 4.03 and 4.41 GeV c.m. energy. The products of cross section times branching ratio are measured for the K − π + , K − π + π + π − , K S π + π − and K − π + π + final states. Upper limits are established for the Cabibbo forbidden decays via π + π − , K + K − , K + K − π + , K + π + π − and π + π − π + . The K − π + π + π − final state is shown to be dominated by K − π + ρ 0 .
THESE PARTIAL CROSS SECTIONS ARE CONVERTED TO TOTAL D INCLUSIVE CROSS SECTIONS USING KNOWN BRANCHING RATIOS AND TABULATED IN M. PICCOLO ET AL., PL 86B, 220 (1979).
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SIG(C=BACKWARD) = SIG(-UP<1 GEV**2)/(1-EXP(-SLOPE)). UP DISTRIBUTION OF EVENTS HAS A PERFECT EXPONENTIAL SHAPE.
A study of the inclusive and semi-inclusive Λ and Λ production in K + p interactions at 32 GeV/ c is presented. The inclusive cross sections for Λ and Λ amount to 0.78 ± 0.05 and 0.42 ± 0.04 mb thus showing a remarkable growth between 16 and 32 GeV/ c with a factor of 1.7 for Λ and 2.8 for Λ . Target and beam fragmentation processes are found to be dominant for Λ and Λ production respectively with the following lower limits for the corresponding cross sections: σ(p → K + ʌ) > 0.5 mb and σ(K + → p ʌ ) > 0.3 mb . Although the early scaling conditions are fulfilled for the Λ production in the target fragmentation region, and Λ production in the beam fragmentation region, scaling is not observed between 16 and 32 GeV/ c in the x and p T 2 Feynman variables. The Λ production is found to be very similar in the K + p inclusive reaction at 32 GeV/ c and in the semi-inclusive reaction K − p → Λ K K X at the same energy. The Λ Λ pair production cross section increases significantly in K + p interactions from 16 to 32 GeV/ c where it reaches the value σ Λ Λ = 47 ± 11 μ b . The cross sections for Λ or Λ produced in association with an identified proton are also given and discussed.
No description provided.
No description provided.
The production of neutral kaons in the reaction K + p → K n + X is studied at the incident momentum of 32 GeV/ c . Inclusive cross sections and single-particle distributions are presented and compared with the data at lower energies. The total inclusive cross section amounts to 7.9 ± 0.3 mb at 32 GeV/ c and is significantly higher than at lower energies due to the rapid rise of multikaon production. The fraction of K n 's coming from the decay of the K ∗ resonances stays roughly constant with energy between 8.2 and 32 GeV/ c . In the central and beam fragmentation regions the single-particle distributions reveal no energy dependence between the 16 and 32 GeV/ c data in contrast with the behaviour at lower energies, while in the proton fragmentation region the data are compatible with the trend observed at lower energies and with theoretical expectations.
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 bubble-chamber experiment based on 304 000 events of p¯p interactions at 2.32 GeV/c is described. The film was automatically scanned and measured by the POLLY II system. Details of the data-analysis methods are given. We report results on cross sections for constrained final states, tests of C invariance, and inclusive pion and ρ0 multiplicity parameters for annihilation final states.
Axis error includes +- 4/4 contribution.
Axis error includes +- 4/4 contribution.
Inclusive production of Λ0 hyperons by 300-GeV protons has been measured at fixed production angles in the laboratory between 0 and 9 mrad and laboratory momenta from 65 to 300 GeV/c. Three different solid targets were used: beryllium, copper, and lead. The A dependence of the data is suggestive of a collision model in which the hadron loses energy and gains transverse momentum as it leaves the nucleus. The experimental results are compared to such a model, and the implications are discussed.
No description provided.
No description provided.
No description provided.
We report on the analysis of inclusive neutral current events produced in neutrino and antineutrino narrow band beams. We find for incident neutrino energies in the range 12–200 GeV and for hadron energies above 12 GeV a neutral to charged current cross-section ratio of R v = 0.293 ± 0.010 for incident neutrinos, and R v = 0.35 ± 0.03 for antineutrinos. These ratios are consistent with the Weinberg-Salam model, with sin 2 θ w = 0.24 ± 0.02.
No description provided.
No description provided.
The charged-current cross sections for neutrinos and antineutrinos on nucleons in the energy range 20–200 GeV are given. Taken in conjunction with the previous Gargamelle results, they show that σ E is almost constant with energy for antineutrinos, and falls with energy for neutrinos. The value of 〈q 2 〉 E decreases with energy for both neutrinos and antineutrinos, and these deviations from exact Bjorken scaling are consistent with those observed in electron and muon inelastic scattering. We find no evidence for new heavy quark states with right-handed coupling.
Measured charged current total cross section.
Measured charged current total cross section.
We present the results of a search at Fermilab for the charmed meson, D∘(1865), produced in association with a prompt muon by 300-GeV/c neutrons. We observe no significant enhancement in high-mass K±π∓ systems and report, at the 95% confidence level, an upper limit of 200 nb/nucleon for the production of a pair of charmed particles and their subsequent decay into a K±π∓ state and a prompt muon.
The cross section for D0 and CHARM particle production is obtained with theassumption that BR(D0 --> K- PI+) = 3 PCT and BR(CHARM --> MU+ X) = 15 PCT.
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