B.S. Yuldashev

Charged and neutral particle multiplicity in π−p and π−n interactions at 40 GeV/c

Abstract Data on the multiplicity of charged particles and π 0 mesons in π − p and π − n interactions are presented and compared to various models. The average π 0 multiplicity tends to increase with increasing number of charged particles.

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.

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.

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.