Search

A study of the inclusive and semi-inclusive Λ and Λ production in K+p interactions at 32 GeV/c is presented. The inclusive cross sections for Λ and Λ amount to 0.78 ± 0.05 and 0.42 ± 0.04 mb thus showing a remarkable growth between 16 and 32 GeV/c with a factor of 1.7 for Λ and 2.8 for Λ . Target and beam fragmentation processes are found to be dominant for Λ and Λ production respectively with the following lower limits for the corresponding cross sections: σ(p → K + ʌ) > 0.5 mb and σ(K + → p ʌ ) > 0.3 mb . Although the early scaling conditions are fulfilled for the Λ production in the target fragmentation region, and Λ production in the beam fragmentation region, scaling is not observed between 16 and 32 GeV/c in the x and pT2 Feynman variables. The Λ production is found to be very similar in the K+p inclusive reaction at 32 GeV/c and in the semi-inclusive reaction K − p → Λ K K X at the same energy. The Λ Λ pair production cross section increases significantly in K+p interactions from 16 to 32 GeV/c where it reaches the value σ Λ Λ = 47 ± 11 μ b . The cross sections for Λ or Λ produced in association with an identified proton are also given and discussed.

The inclusive production of Ξ+ and Ξ− hyperons is investigated in K+ p interactions at 32 GeV/c. The production cross sections, 36.4±9 μb for the Ξ+ and 6.5±3 μb for the Ξ−, are rising strongly with energy similarly to Λ and Λ production in K+ p interactions. The Ξ+ are produced preferentially in the forward direction in the c.m.s., while the Ξ− are produced dominantly backwards. The average transverse momenta 〈pT〉Ξ+=0.73±0.09 GeV/c and 〈pT〉Ξ−=0.58±0.09 GeV/c.

We present results on a number of non-diffractive two-body channels contributing to reactions K+p→K0π+p and K+p→K+π−π+p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K+ beam of 32 GeV/c at the Serpukhov accelerator. Total cross sections are given for the final states K ∗+ (890) p , K ∗+ (1420) p , K 0 Δ ++ (1232), K ∗+ (890) p , Δ ++ (1232), K ∗0 (1420) Δ ++ (1232), K ∗0 (1780) Δ ++ (1232) and K ∗0 (890) Δ ++ (1950) . The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied.