R. W. Kraemer

Strange particle production from π−p interactions at 1.69 GeV/c☆

The three-body final states Σ±π∓K0, Σ0π0K+ and Λπ0K+0 produced from πp interactions at 1.69 GeV/c are examined. The quasi-two-body state Λ(1405)K0 is discussed in detail. In particular, the spin of Λ(1405) is determined, via the method of Byers and Fenster, to be consistent with 12. The Σ±π∓ mass spectrum is compared to that produced by various zero-range and effective-range parametrizations and the Λ(1405) is found to have a mass of 1405 MeV and width of 45–55 MeV. Production and decay characteristics of the quasi-two-body states Σ(1385)0K0 are reported.

KN data and Λ (1405)

A re-analysis of low-energy KN data has been made to investigate the effects of imposing constraints below the elastic threshold. Our results show that without below-threshold constraints little information about the parameters of the Λ(1405) can be determined.

Quasi-two-body production in K−n → Σ∓ + mesons at 4.94 GeV/c☆

Abstract Data on the following quasi-two-body reactions produced in K − n interactions at 4.94 GeV/ c are presented: Σ − π 0 , Σ − η 0 , Σ − ϱ 0 , Σ − ω 0 , Σ − η ′ 0 , Σ − φ 0 , Σ − f 0 , Σ − f′ 0 , Λ (1405) π − and Λ (1520) π − . Cross sections, four-momentum transfer distributions, and density matrix elements are discussed. Assessment of possible exchange mechanisms and comparisons with the predictions of the quark model are made.

Study of the reactions K− + n → Σ± + mesons at 4.93 GeV/c

Abstract Data on ten quasi-two-body reactions produced in K − n interactions at 4.93 GeV/ c are presented. Cross sections, four-momentum transfer distributions, and density matrix elements are discussed. Results of a search for inelastic decays of high mass Y ∗ hyperons are given. Precision measurements of the φ o mass and width are reported. Possible direct channel Y ∗ formation is investigated.

["Λ and K Production in p (pol) p Interactions at 6.0 GeV/c"]

Results on K0 and Λ production in p↑p interactions at 6 GeV are presented. The data are from an exposure of the Argonne 12 ft bubble chamber to a 60% transversely polarized proton beam. Results include data on Λ and K0 inclusive production, and on the reactions p↑p → pΛK+(pΣ0K+). The beam asymmetry parameter for p↑p → K0(K0) + X is determined to be (−0.52 ± 0.12).

LAMBDA AND K0 PRODUCTION IN polarized p p INTERACTIONS AT 12-GeV/c

Results on K0 and Λ production in p↑p interactions at 6 GeV are presented. The data are from an exposure of the Argonne 12 ft bubble chamber to a 60% transversely polarized proton beam. Results include data on Λ and K0 inclusive production, and on the reactions p↑p → pΛK+(pΣ0K+). The beam asymmetry parameter for p↑p → K0(K0) + X is determined to be (−0.52 ± 0.12).

The inclusive reactions π+d → π− + anything and π+d → π−π− + anything at 6 and 24 GeV/c

Inclusive production of π− mesons has been studied with 6 and 24 GeV/c π+ beams interacting in deuterium bubble chambers. The energy dependence of the inclusive spectra is discussed. In comparisons with π+p inclusive interactions, we observe that projectile fragmentation is not independent of the nature of the target at 6 GeV/c. Cross sections and ratios of cross sections are presented. Two-particle correlations are found to be similar at both energies.