The production of K s 0 , Λ and Λ is measured in π + p interactions at 32 GeV/ c . The total inclusive cross sections are found to be 2.07±0.14, 1.00±0.10 and 0.14±0.04 mb, respectively. The energy dependence of total inclusive cross sections and inclusive distributions is discussed and a comparison is made with p, p , K + and K − induced reactions. We find that the factorization hypothesis is satisfied for the inclusive reactions π + p→ Λ X and K + p→ Λ X. Multi-strange-particle production is similar in π + p and K + p interactions at 32 GeV/ c . There is evidence for beam fragmentation in Λ production. The hierarchy of Λ inclusive cross sections in p , K + , π + and K − induced reactions at 32 GeV/ c is qualitatively explained by a quark recombination model. The cross sections for inclusive K ∗ + (892) and Σ + (1385) production in 32 GeV/ c π + p interactions are 1.07±0.57 mb and 0.19±0.08 mb, respectively.
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New experimental results are presented on inclusive production properties of\(\bar \Sigma ^{ *+ } \)(1385) and\(\bar \Sigma ^{ *+ } \)(1385) inK+p interactions at 32 GeV/c. The analysis is based on significantly larger statistics than previously available. A comparison is also made of invariantx-distributions ofK0/\(\bar K^0 \),\(\bar \Lambda \) and\(\bar \Xi ^ +\) and of\(\bar \Sigma ^{ *\pm } \)(1385) andK*+(892). These spectra exhibit regularities expected from the quark-recombination picture when it is assumed that the strange mesons and antibaryons are produced off the strange\(\bar s\)-valence-quark in the incidentK+ meson. Transverse momentum distributions are also presented forK*+(892) and\(\bar \Sigma ^{ *\pm } \)(1385) and found to be very similar. The results on strange antibaryon average multiplicities disagree strongly with a recent version of the additive quark model.
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The production properties ofKs0,\(\bar \Lambda\) andK+p interactions at 32 GeV/c are investigated using the final statistics of the experiment. We present total and semi-inclusive cross sections and aver-age multiplicities. Estimates are given of the diffractive dissociation contributions to total and differential cross sections. Thex-,pT−, and transverse mass dependence of inclusive and semi-inclusive distributions is discussed as well as properties of “prompt”Ks0's. The ratio of “prompt”K890+ (K8900) to “prompt”K0 cross sections is measured to be 1.03±0.12 (0.98±0.17). From a comparison of\(\bar \Lambda\) production inK±p interactions at 32 GeV/c, we estimate a strange sea-quark suppression of 0.26 ±0.02. The double differential cross sections ofKs0's is studied as a function of Feynman-x andpT2, and a Triple-Regge fit performed. The data are compared in detail to versions of the Lund-model for low-pT hadronic collisions.
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Inclusive production of Δ ++ (1232) with >| t p, Δ ++>|<0.6 (GeV/ c ) 2 is studied in 32 GeV/ c K + p interactions. A systematic comparison with the reaction K + p→pX for >| t p,p>| < 0.6 (GeV/ c ) 2 is made. The production properties of the Δ ++ (1232), of associated π + , π − and K 0 production and of the recoiling system X 0 are investigated in detail. The polarization of the Δ ++ and the energy dependence of the total K + π − cross sections, determined by a Chew-Low extrapolation, are presented and discussed.
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Results are presented on total and semiinclusive cross sections, longitudinal and transverse momentum distributions of the tensor mesonsK*+(1430),K*0(1430), andf(1270) observed inK+p interactions at 32 GeV/c. The data are compared withK*+(892).K*0(896) and ϱ0 vector meson production in the same experiment. The shapes of inclusive invariantx-spectra for the strange vector and tensor mesons are found to be rather similar, after removal of diffractive and quasi-two-body channels, in agreement with quark-recombination ideas.
MULT FOR THE TENSOR MESONS CALCULATED AS MULT=SIG(RES)/SIG(N<=8), WHERE SIG(N<=8) IS THE SUM OF TOPOLOGICAL CROSS SECTIONS WITH N <= 8.
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Total and semi-inclusive cross sections, longitudinal and transverse momentum distributions and spin density matrix elements of theK*+(892) andK*0(892) produced in the inclusive reactionsK+p→K*+(892)+X andK+p→K*0(892)+X at 32 GeV/c are studied in detail. The inclusive spectra of theK*(892) and their decay products are compared with pion and neutral kaon production. TheK*+(892) andK*+(892) are dominantly produced by kaon fragmentation processes. The dependence of average transverse momentum <pT> vs.x for resonances has been investigated for the first time.
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A comparative analysis of the global properties of 400 GeV/c proton-proton interactions with and without charm production is presented. Multiplicities, momentum distributions, sphericity and thrust of these interactions are compared.
Charged particle multiplicity distributions for 400 GeV/c proton-proton interactions without charmproduction. The data shown are corrected for trigger losses. No information on cuts and systematic errors, data extracted with g3data.
Charged particle multiplicity distributions for 400 GeV/c proton-proton interactions with charmproduction. The data shown are corrected for trigger losses. No information on cuts and systematic errors, data extracted with g3data.
The production of two high-p_T jets in the interactions of quasi-real photons in e+e- collisions at sqrt{s_ee} from 189 GeV to 209 GeV is studied with data corresponding to an integrated e+e- luminosity of 550 pb^{-1}. The jets reconstructed by the k_T cluster algorithm are defined within the pseudo-rapidity range -1 < eta < 1 and with jet transverse momentum, p_T, above 3 GeV/c. The differential di-jet cross-section is measured as a function of the mean transverse momentum ptmean of the jets and is compared to perturbative QCD calculations.
Total cross section for dijet production. Errors are combined statistics and systematics.
Measured dijet production cross section as a function of the mean jet transverse momentum. Errors include both statistics and systematics.
Measured dijet production cross section as a function of jet pseudorapiditydifference. Errors include both statistics and systematics.
Inclusive distributions of charged particles in hadronic W decays are experimentally investigated using the statistics collected by the DELPHI experiment at LEP during 1997, 1998 and 1999, at centre-of-mass energies from 183 to around 200 GeV. The possible effects of interconnection between the hadronic decays of two Ws are not observed. Measurements of the average multiplicity for charged and identified particles in q qbar and WW events at centre-of-mass energies from 130 to 200 GeV and in W decays are presented. The results on the average multiplicity of identified particles and on the position xi^* of the maximum of the xi_p = -log(2p/sqrt(s)) distribution are compared with predictions of JETSET and MLLA calculations.
Corrected multiplicites and dispersions of charged particles produced in hadronic decays from QQBAR events. The 200 GeV results are a weighted average fromthe 192, 196 and 200 GeV data.
Average multiplicities of identified hadrons produced in hadronic decays from QQBAR events.
Corrected multiplicites and dispersions of charged particles produced in fully hadronic W decays from two W 4Q and 2Q events.
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