L. Gerdyukov

Neutral kaon production in K+p interactions at 32 GeV/c

Abstract The production of neutral kaons in the reaction K+p → Kn + 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 Kns 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.

Charged pion production in 32GeV/c K+p interactions

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.

Inclusive neutral kaon production in 70 GeV/c K+p interactions

Abstract The inclusive production of neutral kaons in 70 GeV/ c K + p interactions is studied with the CERN BEBC bubble chamber. The (semi-)inclusive cross sections are interpreted in terms of the various strangeness channels leading to neutral kaon production. The invariant inclusive cross section for kaon production is studied as a function of p t 2 and the Feynman variable x . The latter distributions are considered both “raw” and corrected for the presence of K 0 s resulting from K ∗ decay. They are compared with the predictions expected from the Regge-Mueller formalism, the recombination model and fragmentation models.

Charged pion production in 70 GeV/cK+p interactions

Inclusive charged pion production is studied in an exposure of BEBC, filled with hydrogen, to an incidentK+ beam of 70 GeV/c. Total cross sections for pion production and inclusive longitudinal and transverse momentum distributions of π−s and of positive particles are presented and compared with data at lower energies. Earlier evidence for scaling in the fragmentation regions is confirmed. The central region π− cross section increases proportionally topLAB−1/4; positive particles show almost no energy dependence atx=0. Particle ratios π+/π− are studied as a function ofx andy* and a comparison with 70 GeV/cK−p data is made. Analysis of structure functions for (ππ) pairs and of particle production associated with π± triggers at large |x| in the context of quark/parton models, provides qualitative evidence for the diquark-quark structure of the proton.

Non-diffractive two-body channels in reactions K+p→K0π+p and K+p→K+π−π+p at 32 Gev/c

Abstract We present results on a number of non-diffractive two-body channels contributing to reactions K+p→K0π+p and K+p→K+π−π+p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K+ beam of 32 GeV/c at the Serpukhov accelerator. Total cross sections are given for the final states K ∗+ (890) p , K ∗+ (1420) p , K 0 Δ ++ (1232), K ∗+ (890) p , Δ ++ (1232), K ∗0 (1420) Δ ++ (1232), K ∗0 (1780) Δ ++ (1232) and K ∗0 (890) Δ ++ (1950) . The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied.

Slow proton andΔ++ production inK+p interactions at 70 GeV/c

The inclusive inelastic processesK+p→pX+ andK+p→Δ++X0 are studied at an incident momentum of 70 GeV/c. The data comes from the Big European Bubble Chamber BEBC filled with hydrogen, exposed to an rf reparatedK+ beam at the CERN SPS accelerator. The inclusive cross section for protons with laboratory momentumpLAB≦1.2 GeV/c is equal to (6.1±0.1) mb. InclusiveΔ++-production is studied for |tp, Δ|<1.0(GeV/c)2. Comparisons are made with otherK+p data and withpp data at 69 GeV/c. Evidence is found for Pomeron exchange at the beam vertex both for slow proton andΔ++-production as well as for absorptive pion exchange at the (p,Δ++) vertex.

Observation in K+p interactions at 32 GeV/c of a narrow state at 2145 MeV/c2 decaying into øπ+

Abstract We present evidence for a new narrow state decaying into oπ + with a mass of 2145 ± 10 MeV/ c 2 and an experimental width of 25 MeV/ c 2 , produced in K + p interactions at 32 GeV/ c . The production cross section σ · BR (→ oπ + ) is equal to 11 ± 3 μb .

A study of multiparticle fragmentation in K+p interactions at 32 GeV/c

AbstractResults are presented on inclusive production of resonant and non-resonant particle systems produced inK+p interactions at 32 GeV/c. We compareK*+(892),

Two-particle K0π+ and K0π− rapidity correlations in K+p interactions at 8.2 and 16 GeV/c and their relation to the K∗(892) resonance production

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