In this Letter, a measurement of inclusive muon production (pμ>2 GeV/c) in e+e− annihilation into hadrons at center-of-mass energies from s=12 to 31.6 GeV is reported. The results agree with the expected semileptonic decays from charmed and bottom mesons.
MUONS PER HADRONIC EVENT.
INVARIANT CROSS SECTION, ASSUMING HADRONIC CROSS SECTION HAS R VALUE OF 3.9 +- 0.5.
We present final results on the inclusive production of the\(\bar K^{*0} (890)\),K*−(890),K*0(890),K*−(890),K*−(1420), and\(\bar K^{*0} (1420)\) resonances inK−p interactions at 32 GeV/c. Total cross sections and invariantx-distributions are determined. Inclusive cross sections of\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) amount to ≃4 mb each, of\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (1420)\) to ≃1 mb and ofK*0(890) to ≃0.8 mb. These values are in agreement with additive quark model predictions. All strangenessS=−1 resonances are predominantly produced in the forward hemisphere, the tensor mesons being more peripherally produced than the vector ones. The\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) density matrix elements andt-distributions are obtained. The unnatural spin-parity exchange contribution to inclusive\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) production amounts to ≳60% at |t|<0.4 GeV2 and decreases with increasing |t|. Whenever relevant, a comparison is also made with available data at other energies.
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The average transverse momentum squared, 〈 p ⊥ 2 〉, of hadrons is studied as a function of W 2 and of Q 2 for ν and ν interactions on an isoscalar target. An increase of 〈 p ⊥ 2 〉 with W 2 is observed for the hadrons emitted forward in the hadronic c.m.s. The p ⊥ dependence of the fragmentation function is found to factorise from the structure function at fixed W , but does not factorise at fixed Q 2 . Unlike the case of forward-going particles, the 〈 p ⊥ 2 〉 of hadrons going backward in the c.m.s. shows no strong dependence on W 2 .
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A study of the reaction π − p → X − p based on 1.27 × 10 6 events, corresponding to a mean sensitivity of 200 events/μb, is presented. Properties of the exclusive channels π − p → π − π 0 p, π + π − π − p, π + π − π − π 0 p, π + π + π − π − π − p and π + π + π − π − π − π 0 p are discussed.
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The reactions K − p → Ξ 0 − (1320) K 0 + , Ξ − (1320) K + (890), Ξ 0 − (1530) K 0 − and Ξ 0 − (1530) K 0 + (890) are studied at 4.2 GeV/ c incident momentum. The data come from a high-statistics bubble chamber experiment with a sensitivity of ∼ 133 events/ μ b. Total anddifferential cross sections are presented. The results are compared to the SU(3)-related processes K + p → pK + and K + p → pK + (890) in the backward hemisphere. In the forward hemisphere “forbidden” peaks are observed and current ideas about them are discussed.
FULLY CORRECTED FOR ALL CUTS AND UNSEEN DECAY MODES.
TOTAL, FORWARD AND BACKWARD CROSS SECTIONS. FULLY CORRECTED FOR CUTS, K0 AND LAMBDA UNSEEN DECAY MODES AND OTHER K*(892) AND XI(1530P13) DECAYS. IN 3-BODY FINAL STATES, THETA REFERS TO THE PI-K SYSTEM.
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As part of a study of large p T phenomena in photon-proton collisions at the CERN ISR, a search for direct single photon production has been performed. A statistical division of the data sample into the fraction consistent with single photon and the fraction due to multiphoton decays of neutral hadrons is accomplished by measuring the average conversion probability for the sample in a one radiation length thick converter. The fraction of the sample attributable to direct single photon production is 〈 γ /all〉 = 0.074 ± 0.012 for 6 GeV/ c < p T 10 GeV/ c , and 〈 γ /all〉 = 0.26 ± 0.04 for p T > 10 GeV/ c , with an additional systematic uncertainty of ±0.05 for both values.
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Inclusive K 0 -production has been measured in e + e - annihilation at a center of mass energy of about W = 30 GeV. The ratio of K 0 + K 0 production to μ + μ - production is R K 0 = 5.6 ± 1.1 (statist. error) ± 0.8 (system.error) This value is about a factor of three higher than R K 0 at W = 7 GeV. The cross sections ( s / β ) d σ /d x is consistent with a scaling behaviour.
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DIFFERENTIAL CROSS SECTION.
INVARIANT CROSS SECTION.
The cross section for the reaction e + e - →π + π - π + π - has been measured at the e + e - storage ring Adone, in the to tal c.m. energy range 1.42–2.20 GeV. The peak and the following descent of the ϱ′(1600) resonance is observed. Using also lower energy data, and assuming that only one resonant amplitude contributes to the observed cross section, the parameters of the ϱ′(1600) are deduced.
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We have analyzed 1113 events of the reaction e + e − → hadrons at CM energies of 12 and 30 GeV in order to make a detailed comparison with QCD. Perturbative effects can be well separated from effects depending on the quark and gluon fragmentation parameters to yield a reliable measurement of the coupling constant α S . At 30 GeV, the result is α S = 0.17 ± 0.02 (statistical) ± 0.03 (systematic). QCD model predictions, using the fragmentation parameters determined along with α S , agree with both gross properties of the final states and with detailed features of the three-jet states.
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Prompt dimuon production has been measured. Events with mass up to 25 GeV/c2 are observed, as well as the J and ϒ resonances. Cross sections are given for J and ϒ production. For the continuum, the scaling function F(τ) is measured at very small values of τ=ms covering the range 0.05<τ<0.20.
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HERE UPSILON = ALL USILON FAMILY. ANGULAR DISTBN. IS SEEN TO BE ISOTROPIC.
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