Search

The proton spectra resulting from 6.3 GeV/ c deuteron break-up on 1 H, 2 H, C, Al and Bi nuclei were measured at an angle of 103 mr (lab) in the momentum interval from 2.6 to 3.6 GeV/ c . The measurements were made at the JINR synchrophasotron with a one-arm magnetic spectrometer on-line with a computer. The results, apart from the effects of pion production, are reasonably reproduced in the framework of the Glauber multiple scattering model, taking into account the relativistic deformation of the deuteron wave function.

The experimental data on d-d collisions at 4.3, 6.3 and 8.9 GeV/ c , exhibiting the two-peak structure in the high-momentum parts of the secondary deuteron spectra at momentum transfers | t | ≈ 0.4–0.8 (GeV/ c ) 2 , are presented. An analysis of the results in terms of the multiple nucleon-nucleon scattering model is given. Some conclusions about the mechanism of the elastic and quasielastic d-d scattering at the above-mentioned momentum transfers are made.

Inelastic interactions of 4 He nuclei at the incident momentum of 4.5 GeV/ c )/nucleon with pure Li, C, Al, Cu and Pb targets were studied in the SKM-200 streamer chamber. Cross sections and their dependence on the target mass number for fragmentation processes were obtained. The multiplicities, transverse momenta and rapidities of negative pions as well as their correlations were analyzed separately for “central” and “peripheral” collisions. A comparison of the results with the predictions of some theoretical models is presented.

An investigation is carried out of the angular distributions and, by magnetic analysis, of the energy spectra of secondary charged particles (mainly protons with energies ⪆ 60 MeV)emitted at angles of 7°, 12.2°, 18°, 24° and 30° in interactions of 660 MeV protons with nuclei of Be, C, Cu and U. The cross sections for emission of such secondary charged particles increase with decrease of the angles. In the order of decreasing energy the various spectral regions of all investigated elements corresponds to diffraction scattering of protons on nuclei (in the small angle region), single quasi-elastic proton-nucleon collisions, π-mesons production on bound nucleons and nuclear cascade. The experimental energy spectra for single quasi-elastic proton-nuclear scattering are compared with the spectra computed in the impulse approximation under various assumptions regarding the momentum distributions of the nucleons in the nuclei. The Be and C data are consistent with a Gaussian nucleon momentum distribution falling to 1/e at an energy of approximately 20 MeV. This means that the mean square value of the nucleon momentum in Be and C nuclei corresponds to an energy of ≈ 30 MeV.

The differential cross sections for the elastic scattering of protons by carbon nuclei and the proton polarization in this process have been measured in the interval1.8° ≦ θ ≦ 9° at 660 MeV. Using a magnetic analysis, elastic proton scattering was separated from inelastic scattering. The best values of the real and imaginary parts of the spin-independent and spin-dependent forward scattering amplitudes have been found to be g NR (0) = −5.05±0.45 fm , g NI (0) = 15.26±0.45 fm h NR (0) = −10.4±13.3 fm , h NI (0) = 37.6±9.3 fm . The values of the integrated optical potentials have been given. The values of r.m.s. radii for the central and spin-orbit potentials have been deduced to be equal to 2.48±0.04 fm and 2.83±0.16 fm. The spin-orbit interaction at 660 MeV is found to be smaller than that at 310 MeV. Conclusions are drawn on the complex value of the spin-orbit potential of the nucleon-nucleus interaction at 660 MeV.

Using a magnetic spectrometer a comparative study was made of the energy spectra of π+ and π− -mesons produced in free pp-collisions as well as in pp- and pn-collisions in deutrons and in carbon nuclei at 654 MeV. The forms of the spectra of pions from deuterium and carbon are found to differ due to: a) a larger extent of correlation of nucleons in carbon nuclei than in deuterons; b) differences in the momentum distributions of nucleons in these nuclei; c) secondary pion-nucleon interactions in carbon nuclei. At ≈ 90° in the centre-of-mass system of two colliding nucleons the ratio of the differential cross sections for the production of π+-mesons on free protons and on protons in deuterons and in carbon nuclei was found to be equal to d σ d ω [ p + p →π + ] H : d σ d ω [ p + p →π + ] D : d σ d ω [ p + p →π + ] C = 1:0.79:0.40 , whereas the yields of π− -mesons per neutron for deuterium and carbon were found to be equal. The measured ratio (dσ+/dω)/(dσ−/dω) of the differential cross sections for the production of positive and negative pions on deuterium and carbon is equal to 10.3±1.3 and 6.0±0.8, respectively. The decrease of the value of this ratio for carbon is caused by a considerable contribution of the secondary exchange interaction π0+ n → π−+p to the yield of π− -mesons.