The effects of resonance production on correlations in final states containing kaons in p p annihilations at 0.76 GeV c have been in detail. We show that correlation distributions of unlike kaon pairs, K S 0 K ± , can be completerly by resonance production. However, for like kaon pairs, K S ) K S 0 , we require the added effects of second-order interference. Using this interference effect we are able to measure the dimensions of the emission region for kaons in p p annihilations at low energy as R = 0.9 ± 0.2 fm.
No description provided.
Based on a sample of 22 four-prong D 0 / D 0 decays produced in hydrogen by 360 GeV/ c π − , we present the following new results: mean lifetime τ = (3.5 −0.9 +1.4 ) x 10 −13 s ; production cross section for x F > 0.0, σ = (10.3 ± 3.5) ωb ; the D → K ± π ± π + π − branching ratio = (7.1 ± 2.5)%.
No description provided.
We report a measurement of the inclusive D/D̄ production cross section in 800 GeV/ c proton-proton interactions. The experiment used the high resolution bubble chamber LEBC exposed to an 800 GeV/ c proton beam at the Fermilab MPS. We obtain σ( D/ D ̄ )=59 −15 +22 μ b (statistical errors), having analysed 25% of the total data sample. Comparison with 400 GeV/ c pp dat a obtained with LEBC at CERN shows a D/D̄ cross section increase by a factor of 1.7 −0.5 +0.7 . This is in good agreement with fusion model calculations.
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We have measured the ratio of the strong coupling constants α s for bottom quarks and light quarks at the Z 0 resonance, in order to test the flavour independence of the strong interaction. The coupling strength α s has been determined from the fraction of events with three jets, measured for a sample of all hardronic events, and for inclusive muon and electron events. The b purity is evaluated to be 22% for the first data set and 87% for the inclusive lepton sample. We find α s ( b ) α s ( udsc ) =1.00± 0.05 ( stat. )±0.06 ( syst. ) .
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The first data on the production of D ∗ (2010) are presented as observed in π − -proton interactions at √ s = 27 GeV . It is found that D ∗ (2010) dominates the total charm D-meson production, without a significant non-central component.
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A study of charged charm production is made at 400 GeV incident energy of protons in nuclear emulsion. A total of 7005 primary stars have been scrutinized to look for charm particle decays in the forward cone within a decay distance of 100–1,000 μm (3,056 stars) and 100–2,000 μm (3,949 stars). In all 10 charm candidates decaying to 3 charged particles plus neutrals have been observed. Background due to secondary interactions for events of such topology is estimated to be ≈3. Background due to strange particle decays is estimated to be negligible. The rest of the events are attributed toΛc+ andD± decays. This leads to a value of 91±35 μb/nucleon for the total charged charm production cross section. Using production cross section forD± from other experiments we obtainΛc+ production cross section as 62±27 μb/nucleon. Two cases of pair production of charm have been seen.
Axis error includes +- 0.0/0.0 contribution (NOT GIVENDECAY-BR(BRN=D+ --> 3CHARGED (NEUTRALS), BR=0.5)//DECAY-BR(BRN=D- --> 3CHARGED (NEUTRALS), BR=0.5)//DECAY-BR(BRN=LAMBDA/C+ --> 3CHARGED (NEUTRALS), BR=0.6)).
Axis error includes +- 0.0/0.0 contribution (NOT GIVENDECAY-BR(BRN=D+ --> 3CHARGED (NEUTRALS), BR=0.5)//DECAY-BR(BRN=D- --> 3CHARGED (NEUTRALS), BR=0.5)//DECAY-BR(BRN=LAMBDA/C+ --> 3CHARGED (NEUTRALS), BR=0.6)).
We report on a study of the inclusive production properties of DD¯ mesons in pp collisions at 800 GeV/c and compare our results to measurements made at lower energies and to the expectations of the QCD fusion model.
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No description provided.
We present a study of the inclusive η production based on 300 000 hadronic Z 0 decays. The measured inclusive momentum distribution can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results with low energy e + e − data, we find that QCD describes both the shape and the energy evolution of the η spectrum. The comparison of η production rates in quark- and gluon-enriched jet samples does not show statistically significant evidence for more abundant production of η mesons in gluon fragmentation.
Differential cross section for inclusive eta production, normalized to the total hadronic cross section.
Differential cross section for inclusive eta production, normalized to the total hadronic cross section.
The production of η(550) and ω(780) mesons is studied in π ± p interactions at 16 GeV/ c and K − p interactions at 10 and 16 GeV/ c . Cross sections for exclusive channels are presented, and for the π + p data differential cross sections are given for quasi-inclusive production where the η or ω is required to be accompanied by charged particles only. Close similarities are observed between η, ω and also ϱ 0 (770) production in terms of longitudinal and transverse variables. By a rough estimate, the η, ω and ϱ 0 inclusive yields are found to be in the ratio 0.32 : 0.85 : 1, respectively, for 16 GeV/ c π + p collisions. For non-peripheral production we estimate this same ratio to be 0.34 : 0.9 : 1.
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
DATA SUPPLIED BY A.A. LEBEDEV.
We present a study of the inclusive production ofK*(892) and ∑t+-(1385)+cc at 3.6 GeV/c from\(\bar p\)p interactions. The sensitivity of the exposure is 35.4 events/μb. Longitudinal and transverse momentum distributions are presented. The indirect production ofKs0 from parentK* and that of Λ's from parent Σ(1385) are studied. The shape of thex distribution of Λ's for\(p\xrightarrow{{\bar p}}\Lambda \) are calculated from\(p\xrightarrow{p}\Lambda \) and\(p\xrightarrow{{\pi ^ -}}\Lambda \) and compared with the experimental distributions. The difference of antiparticle production cross-section ofKs0 in the central region is compared with the expectation from Mueller-Regge formalism.
No description provided.
No description provided.
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