William L. Knight

An enhancement in the ΛΛ invariant mass spectrum

Abstract A 2.1 GeV/ c K − exposure in a heavy liquid bubble chamber has been used to search for the final states KΛΛ. An enhancement in the ΛΛ invariant mass spectrum at 2370 MeV/ c 2 is interpreted as a possible resonance produced in Ξ-nucleon interactions. An estimate of the cross-section for ΛΛ production in Ξ-nucleus reations is given.

An experimental study of the production of neutral pions in p̄p annihilations at 1.6 GeV/c

Abstract The heavy liquid bubble chamber Garamelle has been used to study the rate of production of neutral pions in the pionic annihilation of 1.6 GeV/ c antiprotons on free protons. Preliminary results are presented on the relative cross-sections for most channels together with the mean π 0 multiplicity and the first moments for annihilation into 0-prongs, 2-prongs, 4-prongs and 6-prongs.

The ΛΛ and Ξ− p mass spectra produced by 2.2 GeV/c K− interactions on nuclei

Abstract The S = −2 dibaryon states ΛΛ and Ξ − p have been studied with more than double previous statistics. Earlier indications of an enhancement at M ΛΛ = 2.37 GeV/ c 2 are not confirmed.

An experimental study of the decay rate, form factors and ππ phase-shift in Ke4+ decay

Abstract A sample of 115 K e4 + (e + ) decays has been obtained in a heavy liquid bubble chamber. The decay rate is given, together with the form-factors and mean ππ phase-shift as determined by a maximum likelihoog method.

A measurement of the Ξ hyperon lifetimes and α parameters

In an experiment using a heavy liquid bubble chamber the Ξ hyperon lifetimes and α parameters were measured to be τΞo = (3.04 ± 0.230.26) × 10−10 sec, τΞ− = (1.73 ± 0.070.08) × 10−10 sec, αΞo = −0.84 ± 0.27 and αΞ− = −0.42 ± 0.11. These values agree with measurements which employed different techniques and are consistent with the predictions of the ΔI = 12 rule.

A search for the radiative decay Y0*(1327) → Λγ

Abstract A 2.1 GeV/ c K − exposure in a heavy-liquid bubble chamber has been used to search for the final state Y ∗ (1327) → Λγ . No evidence was found for the existence of this state; an upper limit is placed on the cross-section of the reaction K − + p → Y ∗ (1327) + π + + π − + nπ o , n ⩾ 0 .

The masses of the Ξ hyperons

Abstract Using a 2.1 GeV/ c K − exposure in a heavy liquid bubble chamber, the masses of the Ξ hyperons have been measured to be M ( Ξ 0 ) = 1315.2 ± 0.9 MeV/ c 2 and M ( Ξ − ) = 1321.12± 0.41 MeV/ c 2 . Their mass difference is compared to theoretical predictions.