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AVERAGE OVER ALL TARGETS.
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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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Inclusive Λ production has been studied in K − p interactions at 8.25 GeV/ c using about 69 000 events; the total cross section is found to be 3.35 ± 0.20 mb. A comparison has been made with Σ 0 and Σ(1385) inclusive production. Their influence on the inclusive Λ production is discussed. The inclusive Λ cross section and polarization is interpreted in terms of the triple-Regge model. In the target fragmentation region an effective Regge trajectory is determined which lies closer to the K than to the K ∗ . In the beam fragmentation region the cross-section data indicate an effective Regge trajectory which corresponds to the nucleon, while the polarization data require additional Regge exchanges to be present.
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Inclusive and semi-inclusive production of Λ and\(\bar \Lambda\) inK+p interactions is studied at an incident momentum of 70 GeV/c. Cross sections and single particle distributions are presented and compared with data at lower energies. Scaling is observed between 32 and 70 GeV/c in the Feynmanx variable in the target and the beam fragmentation regions for Λ and\(\bar \Lambda\) inclusive production respectively. An increase of Λ (\(\bar \Lambda\)) production is observed in the beam (target) fragmentation regions, whereas the data at 70 and 32 GeV/c are reasonably close in the central region. The dependence of the Λ(\(\bar \Lambda\)) polarization as a function ofx is measured and found to be in general agreement with the results at 32 GeV/c. The (Λ\(\bar \Lambda\)) pair production cross section increases significantly from 32 to 70 GeV/c. The Λ and\(\bar \Lambda\) production associated with an identified proton is also studied.
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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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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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Final data on topological cross sections are presented. Inclusive single particle distributions for the reactionsK+p→ π±X at 32 GeV/c are discussed and compared with data at lower energies. Early scaling in the fragmentation regions is confirmed, while cross sections in th central region continue to rise with energy even faster than inpp interactions. Thex-andpT-dependence of the π+/π− ratio inK+p interactions is discussed and a comparison of reactionsK+p→ π±X andK−p→ π±X at 32 GeV/c is made in the context of constituent models. We also present transverse momentum distributions, show prominent seagull effects and study how they are influenced by resonance production.
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The production of strange baryons ine+e− annihilation has been studied at centre of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY. Inclusive cross-sections have been obtained forΛ0 andΞ− production and an upper limit has been placed upon the production rate of Σ*±(1385). We measure theΛ0 multiplicity per event to be\(\begin{gathered}\hfill \\0.218_{ - 0.011}^{ + 0.011}\pm 0.021 \hfill \\ \end{gathered} \) and\(0.256_{ - 0.029}^{ + 0.030}\pm 0.025\) at\(\sqrt s=34.8\) and 42.1 GeV respectively. The Ξ− multiplicity per event is found to be\(0.014_{ - 0.003}^{ + 0.003}\pm 0.004\) at\(\sqrt s=34.8 GeV\). An investigation has been made of the extent to whichΛ0 are produced in pairs. TheΛ0 cross-section has been studied as a function of event sphericity.
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