16Op Collisions Research Articles

Comparative analysis of properties of channels of deuteron and tritium production in 16Op collisions at a projectile momentum of 3.25 GeV/c per nucleon

The results of a comparative analysis of channels involving the inclusive production of deuterons and tritons in 16Op collisions at a projectile momentum of 3.25 GeV/c per nucleon are presented. The mechanisms governing proton, deuteron, and triton production in the fragmentation of oxygen nuclei are found to be independent. It is shown that the observed proton-multiplicity correlations are associated predominantly with the character of the primary event of a proton-nucleon collision in 16Op interactions. It is found that, in reactions involving triton production, the contributions of processes leading to an increase in the mean proton multiplicity (n → p + π− and np → pn) and processes leading to its decrease (p → n + π+) compensate each other.

Formation of six-nucleon systems and nuclei in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

The results obtained by studying the production of six-nucleon systems and nuclei that is accompanied by the yield of charged pions in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. It is shown that the correlation of the yield of mirror 3H (3He) nuclei with the production of π+ (π−) mesons is due to the charge-exchange process involving an oxygen-nucleus proton (neutron) knocked out predominantly from an alpha-particle cluster.

Contributions of excited 6Li and 7Li nuclei to the production of 4He+2H and 4He+3H systems in 16O p 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.

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.

Correlation effects in the production of 3He nuclei in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

New experimental data on the dependence of the mean multiplicities and kinematical features of 3He nuclei produced in 16Op collisions at a momentum of 3.25 GeV/c per nucleon on the degree of excitation of the fragmenting nucleus are presented. Strong correlations between the multiplicities of negatively charged pions and 3He nuclei are found.

Special features of deuteron production in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

New experimental data on the dependences of the mean multiplicities and kinematical characteristics of deuterons produced in 16Op collisions at a momentum of 3.25 GeV/c per nucleon on the degree of excitation of the fragmenting nucleus are presented. These experimental data are compared with the predictions of the cascade-fragmentation-evaporation model.

Proton-proton correlations in dp and 16Op interactions

Abstract Correlations between two protons emitted in dp and 16Op collisions at momenta 3.3 GeV/c and 52.6 GeV/c, respectively, are presented. The experimental data have been obtained using the one metre hydrogen bubble chamber exposed to nuclear beams from the synchrophasotron, JINR, Dubna. Data show a clear interference effect as expected for identical fermions. A Gaussian parametrization is used to determine the size of the proton emission source. The root mean square radius of the proton source calculated from the correlation function has been found to be equal to (2.10−0.35+0.43) fm and (2.67−0.38+0.54) fm for d and 16O respectively. It agrees with the known radii of these nuclei.

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.

10.1007/s11450-008-1009-8

New experimental data on the mean-multiplicity distribution of fragments whose charge number ranges between one and eight and on the distribution of the mean kinetic energy of few-nucleon fragments (A = 1–3) are presented versus the 4-momentum transfer from the target proton to the oxygen nucleus in 16Op collisions at a momentum of 3.25 GeV/c per nucleon. These data are systematically compared with the predictions of the cascade-fragmentation-evaporation model.

Cumulative production of three-nucleon nuclei in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

The production of cumulative three-nucleon nuclei (3H and 3He) in 16Op collisions at a momentum of 3.25 GeV/c per nucleon were studied for the first time under conditions of 4π geometry. The slope parameter of the cross section for the production of cumulative three-nucleon nuclei was determined, and new data on correlations of the yields of A = 3 cumulative nuclei, charged particles, and fragments in 16Op interactions are reported. The properties of cumulative and noncumulative events were found to be substantially different, and evidence for the presence of a common universal feature in the mechanisms for the cumulative production of hadrons and light nuclear fragments was obtained.

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.

Formation of cumulative nuclei of 4He in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

The formation of cumulative nuclei of 4He in 16Op collisions at a momentum of 3.25 GeV/c per nucleon was investigated for the first time under conditions of 4π acceptance. The slope parameter of the invariant cross sections for the formation of cumulative nuclei of 4He was determined, and new data on the correlations between the yield of these cumulative nuclei and the yield of charged particles and fragments in 16Op interactions were obtained.

Experimental investigation of charge-exchange processes involving a target proton in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

For the first time, charge-exchange processes involving a target proton in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are studied under conditions of 4π geometry. New data on the mean multiplicities fragments and pions, as well as on inelastic cross sections for topological channels of the fragmentation of an oxygen nucleus in charge-exchange reactions involving a target proton that either are accompanied or are not accompanied by charge transfer to a projectile nucleus, are presented. It is shown that, in 16Op interactions at high energies, charge transfer from a target proton to a projectile nucleus proceeds predominantly via inelastic proton scattering on a neutron of the oxygen nucleus.

Investigation of fragment production for fragment charge numbers between one and eight versus the degree of excitation of the fragmenting nucleus in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

New experimental data on the mean-multiplicity distribution of fragments whose charge number ranges between one and eight and on the distribution of the mean kinetic energy of few-nucleon fragments (A = 1–3) are presented versus the 4-momentum transfer from the target proton to the oxygen nucleus in 16Op collisions at a momentum of 3.25 GeV/c per nucleon. These data are systematically compared with the predictions of the cascade-fragmentation-evaporation model.

Formation of the mirror nuclei 3H and 3He in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

A comparative analysis of the inclusive production of 3H and 3He nuclei in 16Op interactions at a momentum of 3.25 GeV/c per nucleon is performed, and it is shown that the formation of these mirror nuclei occurs under close physical conditions, the distinction between their binding energies having no significant effect on the formation of the nuclei.

Sources of alpha-particle production in 16Op collisions at 3.25 GeV/c per nucleon

Sources of alpha-particle production in 16Op collisions at 3.25 GeV/c per nucleon

Some special features of the momentum spectrum of protons produced in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

The momentum features of protons originating from 16Op collisions at a momentum of 3.25 GeV/c per nucleon are analyzed. It is shown that the degree of excitation of the fragmenting nucleus affects predominantly the shape of the momentum spectrum of protons emitted into the backward hemisphere in the rest frame of the projectile nucleus and partly the shape of the spectra of protons emitted into the forward hemisphere and formed via the mechanisms of Fermi breakup and evaporation.

On the energy spectrum of protons produced in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

New experimental data concerning the mechanisms of the production of protons originating as fragments from oxygen-nucleus interactions in a hydrogen bubble chamber at high energies are presented. It is shown that anomalies observed in the energy spectrum of protons at kinetic energies in the range T = 70–90 MeV are associated with the absorption of slow pions by a quasideuteron nucleon pair.

Inclusive deuteron production in 16Op collisions at a momentum of 3.25 GeV/c per nucleon

Experimental data on inclusive deuteron production in 16Op collisions at high energies were obtained for the first time under conditions of 4π geometry. An irregularity in the momentum spectrum of deuterons in the rest frame of oxygen nuclei is found in the range 0.40 ≤ p ≤ 0.55 GeV/c, and the reasons for its appearance are discussed. The mean multiplicities of secondary fragments are correlated with the presence of deuterons in an event, these correlations being positive for fragments of charge in the range zf ≤ 4 and negative for fragments of charge in the range 5 ≤ zf ≤ 7. This is likely to be due to baryon-charge conservation.

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.