I. A. Ivanovskaya

Neutral strange particle production in π- p, π- n and π- C interactions at 40 GeV/c

Results on the inclusive and topological cross sections for Λ and K0 particles produced in π−p, π−n and π−C interactions at 40 GeV/c are reported. The σΛ(Σ0)π−p values increases twofold from 25 to 40 GeV/c while σKKπ−p increases continuously with the incident momentum. The invariant single-particle distributions in the χ and p⊥2 variables for K10 and Λ particles are presented and compared with the respective ones for π−p interactions at lower energies as well as for pp interactions at 200–300 GeV/c.

Some characteristics of inclusive reactions π-p → π± + ... and π-n → π± + ... at p = 40 GeV/c

Abstract Data on inclusive reactions π − p → π ± + … and π − n → π ± + … at 40 GeV/ c are presented. Inclusive cross sections of the reactions π − p → π ± + … at x = 0 normalized to the inelastic cross section coincide with the ISR results for pp interactions at 500 – 1500 GeV. A similar result has been obtained for the inclusive process π − p → γ + … as well.

Measurement of the decay probability KL → 2πo

Abstract Using the 180-liter ITEP liquid xenon bubble chamber we have measured the branching ratio Γ (K L → 2 π o )/ Γ (K L → 3 π o ) to be (3.7 ± 0.8) × 10 −3 . We find | η oo | to be (2.02 ± 0.23) × 10 −3 .

Production of γ quanta in π−N interactions at 40 GeV/c

Data on the average multiplicity of neutral pions are presented for π−p, π−n and π−C interactions at 40 GeV/c, based on the statistics of 9 432 γ-quanta. A significant increase was found in the average number of π0s per inelastic event as a function of the number of charged particles for these interactions. Average momenta and angular characteristics of the γ-quanta are presented in both the lab. and the c.m. systems. It can be concluded that there is a plateau [in the −1<y∗<1 interval] in the (1σin)dσdy∗=f(y)∗distribution of γ-quanta for π−p interactions and the value of the π−p cross section at y∗=0 agrees quite well with the pp cross section at p=500−1500 GeV/c. This is in favour of the scaling hypothesis in the central region y∗=0 for 40 GeV/c π−p interactions.

Neutral decay modes of the η0 particle

Abstract Results of an investigation of the η0 meson decay modes η0 → γγ, η0 → π0γγ and η0 → 3π0 are presented. The branching ratios of the neutral decay modes have been evaluated.

Transverse momentum correlations in CC and CTa interactions at momentum 4.2 GeV /c/A

Abstract The dependence of the average transverse momentum in the reaction plane on the rapidly variable is studied for particles emitted in central CC and CTa in collisions. The effect is reasonably well described by the Gudima-Toneev cascade. No collective effects are needed.

Correlations in particle production in pion-proton interactions at 40 GeV/c

Abstract Results of the investigation of some correlation effects in π − p interactions at 40 GeV/ c incident momentum are given. On the basis of 2 000 events the dependence of the transverse momenta of π + and π − mesons on the longitudinal momenta was obtained, as well as two- particle distributions for various pion pairs, and correlation functions C ( y 1 , y 2 ) and R ( y 1 , y 2 ). For π + π − pairs R (0,0) = 0.65 ± 0.07 and the correlation length is L = 1.8 ± 0.2 for −1 ⩽ y 1 , y 2 ⩽ 1. For π + π + and π − π − pairs R (0,0) = 0.26 ± 0.10. Comparison of these results with proton-proton data at 200 GeV and at ISR energies suggests that limiting behaviour in two- particle distributions R ( y 1 , y 2 ) for π − p interactions is already reached at 40 GeV.

Inclusive π−p→γ+ anything and π−12C→γ+ anything reactions at 40 GeV/c

Abstract In this paper, some results on inclusive γ and π 0 spectra in π − p and π −12 C interactions at 40 GeV/ c are reported. It is shown that there is no factorization of the structure function f ( q ⊥ , x ) in π − p→ γ + anything reactions for q ⊥ ⩽0.4 GeV/ c and | x |⩽0.16. The π 0 meson longitudinal momentum spectrum in the cms is obtained by applying the method of statistical regularization to the measured γ spectrum. In the range | x |⩽0.02, N π + = N π − = N π 0 within the error limits (±7%). The inclusive γ spectra in π − p and π −12 C interactions indicate that the normalized structure function is the same for both reactions over the central and the π − meson fargmentation regions.

Search for the neutral decays ωO → ηγ and ωO → πOπOγ

Abstract The decays of ω O → ηγ and ω O → π O π O γ are investigated by means of the effective mass method. Decay branching ratios of ω O → ηγ and ω O → π O π O γ are determined.

Investigation of the M(πoπo) effective mass spectrum

Abstract Investigation of the effective mass spectrum of the πo−πo system is carried out in the interval of mass values M(πoπo) ⩽ 1.3 GeV. A peak is observed at M (π o π o ) = 730 ± 15 MeV .