123098563
Production of delta isobars on tantalum nuclei in CTa collisions at a projectile momentum of 4.2 GeV/c per nucleon
A procedure that relies on analyzing the angle between the momenta of the proton and the pion originating from CTa interaction at a projectile momentum of 4.2 GeV/c per nucleon was used to investigate for the first time the production of Δ0 and Δ++ resonances in such interactions and to determine their parameters. The criterion of stability in the parameter a characterizing the background contribution was presented for the first time and was used to reconstruct the mass distributions of Δ0 and Δ++ resonances. The contributions of Δ0- and Δ++-resonance decays to the production of charged pions were estimated. The results of this study are compared with similar data obtained by using the analogous procedure for Δ0 and Δ++ resonances produced on carbon nuclei in CC and 4HeC collisions at a projectile momentum of 4.2 GeV/c per nucleon and in π−12C interactions at a projectile momentum of 40 GeV/c.
123557824
Production of baryon resonances in + C interactions at 40 GeV/c
In conditions of 4{pi}-geometry, the production of {delta}{sup ++} and {delta}{sup 0} resonances in {pi}{sup -}+ {sup 12}C interactions at 40 GeV/c was investigated for the first time. The masses and widths of resonances were obtained from an analysis of the experimental and background invariant mass distributions of p{pi}{sup {+-}} pairs. The fractions of charged pions coming from {delta}{sup ++} and {delta}{sup 0} decay as well as the inclusive cross-section of {delta}{sup ++} and {delta}{sup 0} production were determined. The results obtained were compared to the recent results on {delta}(1232) production in {sup 4}He +C and C+C collisions at 4.2 GeV/c per nucleon, and Ni+Ni and Au+Au collisions at energies between 1 and 2A GeV.
120616762
On the mechanisms of cumulative-proton production in high-energy hadron-nucleus and nucleus-nucleus collisions
The importance of studying processes involving cumulative-proton production stems from their direct relation to the formation of multiquark configurations, so-called fluctons, in a nucleus owing to nucleondensity fluctuations in which two or more nucleons occur at a distance shorter than 1 fm from one another. According to [1], multiquark configurations may arise in two different physics patterns. The first, caused by a fluctuation of the target-nucleus density, is referred to as a cold model, while the second, associated with nuclear-matter compression occurring under the effect of an incident hadron or a projectile nucleus and leading to the formation of dense quark bags, is called a hot model. It should be noted that, in early interpretations, the production of cumulative protons was related to the Fermi momenta of nucleons. However, the calculations that took into account the Fermi momentum of nucleons [2] showed that the spectrum of fast ( p> 500 MeV/c) cumulative protons cannot be described in this way. In the present study, we examine new features of the process of cumulative-proton production—in particular, we analyze the behavior of the mean multiplicity of cumulative protons as a function of the charge and mass numbers of the target nucleus. Previously, our group studied [3–5] cumulativeproton production in π −12 С, pС, 4 НеС, СС, 16 Op, and p 20 Ne collisions at primary energies in the range 3–300 GeV and, on the basis of a vast statistical data sample, confirmed the universal regularity that the slope parameter of inclusive cross sections for cumulative protons in the cumulative number β is independent of the primary energy and mass of the incident particle or nucleus. It was shown that the fraction of events involving cumulative-proton production on a carbon nucleus is sensitive to the
116898559
Study of fragmentation of oxygen nucleus in sup 1 sup 6 Op-interactions at 3.25 A GeV/c momentum
195343399
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.
123656934
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.
121847480
Multiplicity of charged particles in π−-carbon interactions from 4 to 40 GeV/c
Abstract We have measured the multiplicities of secondary charged particles produced in the collisions of π − mesons with carbon nuclei at momenta of 4.0, 5.0, 7.5 and 40.0 GeV/ c . The distribution of the number of visible protons does not change with the primary energy. There is observed an anomaly around n S = 3–4 for the multiplicity distribution of shower particles at 40 GeV/ c . Both the average multiplicities of shower and negative particles increase logarithmically with the momentum of the primary π − meson. The multiplicity of secondaries obeys KNO scaling. There are correlations, increasing with energy, between average multiplicities of charged fast particles and the number of slow protons. The presented experimental data are analyzed in the framework of new models proposed for inelastic hadron-nucleus collisions.
121855103
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.