A. A. Yuldashev

Fragmentation of relativistic oxygen nuclei in interactions with a proton

Abstract.The data on investigation of inelastic interactions of 16O nuclei in a hydrogen bubble chamber at an incident momentum of 3.25 A GeV/c are presented. Separate characteristics as fragments isotope composition and topological cross-sections of fragmentation channels are given. The processes of formation of light fragments and unstable nuclei, and the break-up of the 16O nucleus into multicharge fragments are investigated. A comparison between the experimental data and the calculations of the cascade fragmentation evaporation model (CFEM) is made. The observed singularities of the interactions point out the important role of the nucleus α-cluster structure in the formation of the final products.

Formation of multinucleon systems and nuclei with mass numbers of 6 and 7 in 16Op interactions at a momentum of 3.25 GeV/c per nucleon

The results of a comparative analysis of the multiplicities of singly and doubly charged accompanying particles in the channels involving the production of six- and seven-nucleon systems in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are reported. Cross sections for the yield of multinucleon systems and mean multiplicities of accompanying particles are found. The experimental data are compared with the predictions of the cascade—fragmentation—evaporation model.

Cross sections for the production of stable and unstable isotopes with charge numbers from one to eight in 16Op collisions at 3.25 A GeV/c

New experimental data are presented for the inclusive cross sections both for the production and for the yield of stable and unstable isotopes with charge numbers from one to eight in 16Op collisions at 3.25 A GeV/c.

On correlations in the production of charged pions and mirror nuclei 3H and 3He in 16Op interactions at a momentum of 3.25 GeV/c per nucleon

Previous investigations into fragmentation processes revealed that independent fragment production is observed even for light nuclei [1]. However, the question of whether there is an interplay of the mechanisms of production of secondary particles (pions) and fragments in hadron–nucleus collisions at high energies or whether they rule out each other has not received adequate study. Clearly, it is worthwhile to study correlations in the production of various types of particles and fragments produced in hadron–nucleus collisions at high energies in order to clarify this question.

Production of mirror nuclei {sup 7}Li and {sup 7}Be in {sup 16}Op interactions at a momentum of 3.25 GeV/c per nucleon

Results of a comparative analysis of processes leading to the production of mirror nuclei 7Li and 7Be in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. A comparison of associated multiplicities of accompanying particles is performed. The first results on the mean multiplicity of neutrons appearing as fragments are described.

Production of mirror nuclei 7Li and 7Be in 16Op interactions at a momentum of 3.25 GeV/c per nucleon

Results of a comparative analysis of processes leading to the production of mirror nuclei 7Li and 7Be in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. A comparison of associated multiplicities of accompanying particles is performed. The first results on the mean multiplicity of neutrons appearing as fragments are described.

Breakup of an oxygen nucleus to light fragments of mass number in the range A ⩽ 4 in 16Op interactions at a momentum of 3.25 GeV/c per nucleon

New experimental data on the correlations of the yields of 4He and 2H nuclei in semi-inclusive reactions involving by the production of 3He and 3H mirror nuclei in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. The mean multiplicities of protons and neutrons appearing as fragments are found to be independent of the number of associated deuterons, this indicating that a considerable part of these fragments originate from the breakup of the alpha-particle clusters forming the oxygen nucleus.

Phenomenological analysis of the channels of the production of three and four alpha particles in 16Op collisions at 3.25 GeV/c per nucleon

A phenomenological analysis of the channels of the production of three and four alpha particles in 16Op collisions at 3.25 GeV/c per nucleon is performed for the first time under conditions of 4π geometry. The experimentally observed azimuthal asymmetries and collinearity are described on the basis of a phenomenological model that assumes that the excitation of the nucleus involved is peripheral and that its decay is statistical. It is shown that the azimuthal asymmetries in question are due to the transverse motion of the fragmenting nucleus. The mean transverse momentum of alpha particles and the collinearity of their emission in the reaction plane are found to be independent of the transverse-momentum transfer to the nucleus involved.

Contribution of excited nuclei 12C* to the channel of three-alpha-particle production in 16Op collisions at a momentum of 3.25 GeV/C per nucleon

A phenomenological analysis of the channel involving the production of three alpha particles in collisions of relativistic oxygen nuclei with protons is performed for the first time. It is shown that one-third of it is saturated by the decay of an excited nucleus 12C*, while the remaining part is due to direct Fermi breakup or the quasielastic knockout of one alpha-particle cluster from a loosely bound residual nucleus consisting of three alpha particles. The results obtained by simulating the decay of the excited system involving three alpha particles for an isotropic phase space describe experimental data satisfactorily at moderate values of the excitation energy (ΔE*<15 MeV).

Contributions of excited 6Li and 7Li nuclei to the production of 4He+2H and 4He+3H systems in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

New experimental data on the cross sections for the yield of excited 6Li* and 7Li* nuclei and on their contributions to the production of 4He + 2H and 4He+3H light dinuclear systems in 16Op collisions at a momentumof 3.25 A GeV/c per nucleon are presented.