G. Vassiliadis

Spin-parity analysis of the E meson centrally produced in the reactions π+ p → π+ (K01K±K±) p and pp → p(K01K±π ±)p at 85 GeV/c

Results are presented of a spin-parity analysis on a sample of ∼ 1000 E mesons centrally produced in the reactions (π+/p) p → (π+/p) (K01K±π∓) p at 85 GeV/c. The E quantum numbers are determined to be JPC = 1++. Its decay in this channel is consistent with being 100% into K∗K + c.c. and no evidenceis seen for a δ π decay mode where δ → KK. The mass and width were determined to be M = (1425 ± 2) MeV and Γ = (62 ± 5) MeV.

Inclusive V0 production in pp interactions at 12 GeV/c

Results are presented on the inclusive reactions pp → K0X, pp → ΛX and pp → ΛX at an incident antiproton momentum of 12 GeV/c in BEBC. The cross sections are studied as functions of the Feynman scaling variable x, the rapidity, the transverse momentum of the V0 and the missing mass squared. The dependence of the Λ and Λ polarization on x are also studied. Comparisons with proton-proton data at 12 GeV/c are also made. Finally, events with two detected V0 are analyzed in order to study correlations arising from the production of two strange neutral particles.

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.

Inclusive production of K*(890), Σ(1385) and S*(993) resonances in pp interactions at 12 GeV/c incident momentum

The reactions pp→K*(890)X, pp→Σ±(1385)X and pp→S*(993)X at 12 GeV/c incident momentum have been studied using 19 000 events with a visible V0 decay in BEBC. Inclusive production cross sections of these resonances as a function of transverse momentum and rapidity are presented. The contribution of annihilation to the production of the K*(890) is investigated from a comparison with the corresponding pp data.

Evidence for a narrow peak in Ksoπ±π+π- at 2.6 gev in 12 gev/ cpp interactions

Abstract We report the evidence for a narrow charged peak (5.5 s.d.), which we suggest calling the I, in the 6-prong-V 0 topology of p p interactions at 12 GeV/ c . The mass, widht and the product of cross section σ I times the branching ratio BR into the final state (K s o τ±τ + τ − are found to be: M I =2.60 ± 0.01 GeV / c 2 , Γ I ⩽ 0.018 GeV / c 2 , σ I ·BR≈20 μbarn

Inclusive photon and π0 production inK+p interactions at 70 GeV/c

Inclusive and semi-inclusive cross sections and distributions of γs and π0s inK+p interactions at 70 GeV/c are presented. The results are compared to other experiments and to the Lund model for low-pT hadron collisions.

Cross sections for exclusive channels in\(\bar pp\) reactions at 12 GeV/c

The data obtained in an exposure of BEBC to an r.f. separated beam of antiprotons at 12 GeV/c are used to derive exclusive cross sections for reactions having one or more neutral strange particles in the final state. Particular attention is given to the estimation of the background. An upper limit of the cross section for the inclusive production of the charmed mesonD* is also given.

Inclusive V0 Production in anti-p p Interactions at 12-GeV/c

Results are presented on the inclusive reactions pp → K0X, pp → ΛX and pp → ΛX at an incident antiproton momentum of 12 GeV/c in BEBC. The cross sections are studied as functions of the Feynman scaling variable x, the rapidity, the transverse momentum of the V0 and the missing mass squared. The dependence of the Λ and Λ polarization on x are also studied. Comparisons with proton-proton data at 12 GeV/c are also made. Finally, events with two detected V0 are analyzed in order to study correlations arising from the production of two strange neutral particles.

A search for charmed particle production in pp interactions at 12 GeV/c

A search for charmed particles (D mesons, D* mesons and λc baryons) produced in pp interactions at 12 GeV/c incident beam momentum has been carried out using 16 500 events with a visible V0 decay in a 10 event/μb experiment in BEBC. No enhancements are observed in the invariant mass distributions of Ks0 + nπ (n = 1-5) and λ(λ) + nπ (n = 1-3) in the regions of the known charmed particle masses. The upper limits for the product of the inclusive production cross sections times decay branching ratios of D, D* and λc particles as well as the production of pairs of charmed mesons are calculated at 95% confidence level. The Ks0 yields per annihilation event in e+e- and pp interactions are compared at various energies.

Ω/Ξ production ratio in S‐W

We have measured the (Ω−+Ω+)/(Ξ−+Ξ+) production ratio in central S‐W collisions to be 0.8±0.4 at central rapidity and pT≳1.6 GeV/c.