Search

Inclusive production of vector and tensor mesons is studied in a K−p experiment at 32 GeV/c in the MIRABELLE bubble chamber. The K∗0(890), ϱ0 and ω cross sections are comparable, about 4 mb each. The K∗0(1420 and cross sections are also comparable, about 1 mb each. The K∗o+(890), Φ, K∗o−(1420) and f cross sections beam fragmentation; ϱ production is almost forward-backward symmetric in the c.m.s. The pT production slopes of K∗o−(890) and ϱ are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ≅50% (≅60%) of final-state pions

The general features of pp interactions at 32 GeV/c are analysed in a bubble chamber experiment with a statistics of 5.2 μb/event. The inclusive production of neutral strange particles and pions is analysed and compared to results obtained at other energies and in pp interactions. Total cross sections are determined for various 4C reactions and the relative contributions of diffractive dissociation and ΔΔ production to the reaction pp→ppπ+π− are estimated.

The inclusive cross section and the average multiplicity are evaluated for most of the charged (π±, p, K±) and neutral (γ, π0, K0, K0, Λ, Λ, n) particles produced in 32 GeV/c K−p interactions; corresponding results are obtained for each charged topology separately. New results are given for the total charged multiplicity cross sections. The average longitudinal momentum of neutrals is found to be roughly equal to that of charged particles. The π+ and π− multiplicity distributions are reconstructed and compared to the π0 and to the total charged multiplicity distributions.

We investigate the main features of the reaction pp → ppπ+π− at 69 GeV/c from data obtained in the Mirabelle bubble chamber at Serpukhov. A search for a double pomeron exchange mechanism contribution leads to an upper limit of ⋍20 μ b for M(π + π − ) ⩽ 0.7 GeV under reasonable assumptions. The four-body final state is dominated by proton diffractive dissociation p → pπ+π− (mostly Δ++π−). The cross section for this process, as well as the t production slope and the decay distributions (of the Δ++) show little variation in comparison with lower energy data.

Results are presented on the inclusive π± production in K−p interactions at 32.1 GeV/c. The invariant longitudinal distributions have been calculated both for π+ and π− in the backward c.m. hemisphere and extrapolated in the forward hemisphere under some physical assumptions. The inclusive cross sections for π+ and π− amount to 32.9 ± 1.5 mb and 35.0 ± 0.7 mb respectively. The energy dependence of the inclusive pion production has been analyzed in the framework of Mueller-Regge phenomenology both in the proton fragmentation and in the central region.

Topological cross sections and average charge multiplicities 〈 n c 〉, are presented for 33.8 GeV/ c K − p and 50 GeV/ c π − p interactions observed in the 4.5 m Mirabelle hydrogen bubble chamber at Serpukhov. Values for 〈 n c 〉 of 5.16 ± 0.08 and 5.71 ± 0.13 were found for the K − p and π − p reactions, respectively. The two quantities 〈 n c 〉 and the correlation term ƒ; 2 have been tabulated for π ± p, K ± p, and pp reactions at various energies. It is shown that the energy variation of each of these two quantities is described by a universal curve when plotted against the Q -value of the reaction. The ratio 〈 n c 〉/ D , where D is the dispersion of the multiplicity distribution, is found to approach the constant value of 2 from above as the energy increases.