W. Beusch

Observation of resonance in the KO1KO1 system

Abstract We have analyzed 2560 events in the final-state K O 1 K O 1 n produced in π − p interactions at 5, 7 and 12 GeV/ c . We observe the S ∗ (1070), f O and A 2 decaying into K O 1 K O 1 . Resonance parameters, cross sections, and branching ratios are given.

Further results on the charge exchange pp →nn at 5, 6, 7 and 9 GeV/c☆

Data are presented on the total and differential cross sections at 5, 6, 7 and 9 GeV/c for the reaction pp →nn. The results are compared with the Regge-pole and the coherent droplet models.

Performance of a large magnet spark chamber

Abstract The description of a 60 × 67 × 160 cm3 spark chamber in a 10.5 kG magnetic field and a report on its performance are given. This instrument was used at the CERN Proton Synchrotron for the detection of the neutral (and non-π0) reaction products of π−, K− and p on hydrogen. The sources of the systematic deviations in spark position have been investigated and corrections have been devised to compensate for them. The residual random errors are: 1. 1. the rms deviation of individual sparks from the fitted trajectory σy = 0.18 mm in space. 2. 2. the rms measurement error σy meas = 0.09 mm in space. The MDM of the instrument is 1000 GeV/c and the rms error in the mass of K10 mesons of 7 GeV/c momentum is Δm = 7.3 MeV/c2.

The charge exchange pp → nn at 5, 6, 7 and 9 GeV/c☆

Abstract The reaction p p → n n has been studied with a magnet spark chamber system. The results obtained on the total cross section at 5, 6, 7 and 9 GeV/c and on the differential cross section at 7 GeV/c are given.

A study of the backward peak in the ΛKo associated production at 5, 7 and 12 GeV/c☆

Abstract Data are presented on the total and differential cross-sections for the backward peak in the ΛK o associated production. The polarization of the Λ is found to be consistent with 100%.

A study of the reaction π− + p → Λ + Λ + n at 7 and 12 GeV/c

Abstract Over 100 unambiguous π − + p → Λ + Λ + n events have been observed in a magnet spark chamber. The data provide good evidence for peripheral production of Λ Λ and n Λ (via meson exchange) and against peripheral n Λ (double baryon exchange). No resonances in the Λ Λ system are observed. Angular distributions and Λ( Λ ) polarizations are analysed.