The data obtained by the bubble chambers and nuclear photoemulsion in the interval of energies from 4 up to 400 GeV have been analysed in the quasirapidity scale with the purpose of secondary hadrons' clasterisation study. The new method of the multiparticle correlations, independing on the energy, quasirapidity interval chosen and models, has been proposed in this work. It is shown that the density correlations of different signs in the analysed events are observed. Among their the events with maximal densities, in which the correlations factor does not differ from background beyond a double statistical error, are not observed. However are bumps at 400 GeV the values of which require an affimation.

Scanning results ofp, d, he, and12C interactions on Ta plates and in propane are presented. Inelastic cross sections are determined. They agree with geometrical models. General characteristics of pion multiplicity distributions are analyzed and compared with results from nucleon-nucleon interactions. Average multiplicities of negative pions are found to depend on the number of interacting beam nucleons.

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(y1, y2) and R(y1, y2). For π+π− pairs R(0,0) = 0.65 ± 0.07 and the correlation length is L = 1.8 ± 0.2 for −1 ⩽ y1, y2 ⩽ 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(y1,y2) for π−p interactions is already reached at 40 GeV.

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.

In the study of interactions of 60 GeV/ c π − mesons in nuclear emulsion some peculiarities of the prong-number distribution and the angular distribution of secondaries have been observed. They are interpreted in terms of the coherent production of three and five pions on emulsion nuclei. The cross section for these reactions increases with the increasing energy.