I.A. Ivanovskaya

Multiplicity, momentum and angular characteristics of π− mesons forpC,dC, αC and CC interactions at 4.2 GeV/c per nucleon

Light ion collisions with carbon target at 4.2 GeV/c/N are studied. Pion multiplicity distributions, momentum and angular spectra are analysed. These data are described in terms of models assuming independent interactions of nucleons from the projectile nucleus with the target.

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.

Asymmetry of π− meson emission in nucleus-nucleus collisions as a measure of the target-to-projectile ratio of the numbers of interacting nucleons

Experimental data on the forward-backward asymmetry of π- emission in (d,4He,12C)181Ta interactions atp/A=4.2 GeV/c are presented. The absolute value of the asymmetry coefficient of the inclusive π- production in the nucleon-nucleonCMS decreases asAp−0.35 with increasing atomic mass of projectile nucleus. A method of obtaining the target-to-projectile ratio of the numbers of participant nucleonsNt/Np through measuring the velocity of the symmetric pion emission system is proposed. It has been found that Nt/Np∼Ap−0.73.