Search

We present a comprehensive study of the inclusive production of V0V0 pairs (V0=Λ, Λ̄ or KS ) by Σ- and π- of 340 GeV/ c momentum and neutrons of 260 GeV/ c mean momentum in copper and carbon targets. In particular, the dependence of the xF spectra on the combination of beam-particle and produced V0V0 pair is investigated and compared to predictions obtained from PYTHIA and QSGM calculations. The data and these predictions differ in many details, the agreement can at best be termed as qualitative. A signal from decays of the tensor meson f’2(1525) was observed in the KS KS mass distribution and inclusive production cross sections were measured. No signal was found from the double-strange H-dibaryon decaying to ΛΛ. [ABSTRACT FROM AUTHOR]

We report on the observation of a KSp resonance signal at a mass of 1765 ± 5 MeV/ c 2, with intrinsic width Γ = 108 ± 22 MeV/ c 2, produced inclusively in Σ--nucleus interactions at 340 GeV/ c in the hyperon beam experiment WA89 at CERN. The signal was observed in the kinematic region xF>0.7, in this region its production cross section rises approximately linearly with (1-xF), reaching BR(X→KSp)dσ/dxF=(5.2±2.3)μb per nucleon at xF=0.8. The hard xF spectrum suggests the presence of a strong leading particle effect in the production and hence the identification as a Σ*+ state. No corresponding peaks were observed in the K-p and Λπ± mass spectra. [ABSTRACT FROM AUTHOR]

We have measured the polarization of Λ hyperons produced inclusively by a Σ- beam of 340 GeV/c momentum in nuclear targets. From a sample of 9.5 millions of identified Λ decays, polarizations were determined in the range xF > 0.1 and pt ≤ 1.6 GeV/c. The polarization w.r.t the production normal is mainly positive for xF ≥ 0.3. At fixed values of xF, it increases with pt to a maximum between pt = 0.5 and pt = 1 GeV/c,and then decreases to zero or even negative values, in sharp contrast to the plateau above pt = 1GeV/c observed in inclusive Λ production by protons. [ABSTRACT FROM AUTHOR]

We report on a measurement of the inclusive cross sections of Λ, Λ, KS0 and Ω- production by ∑- and π- of 345 GeV/c momentum and by neutrons of 260 GeV/c mean momentum in copper and carbon. The differential cross sections as function of pt² show a distinct non-gaussian behavior above 1.2 (GeV/e)². A comparison of the xF-dependence of ΛΛ, A and K0 production with calculations using PYTFHA and the QGSM model is discussed. [ABSTRACT FROM AUTHOR]

We report on the observation of a KSp resonance signal at a mass of 1765 ± 5 MeV/ c 2, with intrinsic width Γ = 108 ± 22 MeV/ c 2, produced inclusively in Σ--nucleus interactions at 340 GeV/ c in the hyperon beam experiment WA89 at CERN. The signal was observed in the kinematic region xF>0.7, in this region its production cross section rises approximately linearly with (1-xF), reaching BR(X→KSp)dσ/dxF=(5.2±2.3)μb per nucleon at xF=0.8. The hard xF spectrum suggests the presence of a strong leading particle effect in the production and hence the identification as a Σ*+ state. No corresponding peaks were observed in the K-p and Λπ± mass spectra. [ABSTRACT FROM AUTHOR]