A.N. Solomin

Interaction cross sections and negative pion multiplicities in nucleus-nucleus collisions at 4.2 GeV/c per nucleon

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.

Peripheral and central nucleus-nucleus collisions at 4.2 GeV/c per nucleon

Experimental data on interactions of relativistic p, d, He and C nuclei with carbon and tantalum nuclei are presented. The data come from the 2−m propane bubble chamber with an internal tantalum target. It is found that interaction cross sections for carbon projectile fragments with chargesZ=5,6 are 10% greater than expected. In central C+C collisions and in multinucleon interactions of d, He and C with tantalum a contribution is observed from cumulative interactions irreducible to the superposition of NN-collisions taking into account final state interactions, rescattering effects, etc.

Characteristics ofπ− production in the collisions of 4.2 GeV/c/nucleond, α and12C beams with tantalum

One particle distributions ofπ− produced in the collisions of deuterons, alphas, and carbon nuclei with Ta target at 4.2 GeV/c per nucleon momentum, registered in the propane bubble chamber, are presented. Comparison of the data with multiple scattering model and additive quark model is attempted.

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.

Scaling of semi-inclusive cross sections with respect to longitudinal and transverse momenta

Abstract The semi-inclusive one-particle transverse and longitudinal momenta spectra of π ± mesons have been studied in the centre-of-mass system for π − p interactions at 40 GeV/ c . These data are compared with similar data from pp interactions at 300 GeV/ c and lower energies. Distributions in the variables p T /〈 p T 〉 and p L /〈 p L 〉 reveal scaling properties, which are found to be substantially independent of the nature of the projectile, of the incident energy and of the prong multiplicity. These spectra are reasonably described by universal functions.

Inclusive two-particle correlations in 40 GeV/c π−p collisions and particle production mechanisms

Abstract Inclusive two-particle correlations in rapidity variables between π + π − , π + π + and π − π − obtained in 40 GeV π − p collisions are discussed in the framework of the Mueller Regge model and the multiperipheral cluster model. The data show features similar to the data reported at much higher energies from the CERN ISR. This behaviour is more easily understood from the multiperipheral cluster model. Data on transverse momentum correlations in the same reactions can be qualitatively understood from the same model.