Search

The statistical event-by-event analysis of inelastic interactions of 16O and 32S nuclei in emulsion at 60 A GeV/c and 200 A GeV/c reveals the existence of groups of high multiplicity events belonging to very central nuclear interactions with Gaussian pseudorapidity distributions for produced particles as suggested by the original hydrodynamic-tube model. Characteristics of these events are presented. The experimental observations are interpreted as a result of quark-gluon plasma formation in the course of central nuclear interactions., 8 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1807.01234

The production of quark-gluon plasma is discussed within the hydrodynamic theory of multiparticle hadron production in head-on collisions of nucleons with nucleons and nuclei. In searches for collisions of a proton with a tube of a track-emulsion nucleus, the use of parametrically invariant quantities is proposed. An experimental verification of statistical models involving qualitatively different pseudorapidity distributions of weakly ionizing secondary particles is performed. The results of this verification are discussed.

Inter- and intragroup azimuthal correlations of target and projectile fragments and of shower particles in the interactions between gold nuclei of energy 10.6 GeV per nucleon and silver and bromine nuclei of a track emulsion are studied at intermediate values of the impact parameter. The asymmetry index β′1 and the collinearity index β′2 of groups’ asymmetry vectors are used to study azimuthal correlations between two and three groups of particles. The interplay of effects of intra- and intergroup azimuthal particle correlations is investigated.

Charged secondaries from collisions of gold nuclei with track-emulsion nuclei showed azimuthal correlations consisting in (i) the asymmetric emission of projectile and target fragments in opposite directions and (ii) an azimuthal quasicollinearity of shower particles in individual events. The measurement errors were investigated and taken into account. The experimental data in question can be interpreted within the model of Gaussian distributions of transverse momentum components.

Intra-and intergroup azimuthal correlations of projectile and target fragments are found in collisions between gold and emulsion nuclei. The statistical significance of these correlations is high. The methodological distortions associated with the measurement errors are investigated in detail and are taken into account.

Phenomenological Monte Carlo model of peripheral interactions of 9Be nuclei with emulsion nuclei at [Formula: see text][Formula: see text]GeV with formation of an excited 9Be* nucleus and its subsequent breakup, either directly or through formation of an intermediate 8Be nucleus, into two [Formula: see text]-particles and a neutron was constructed. A comparative analysis of the experimental data on angular correlations and momentum spectra of [Formula: see text]-particles, coming from a breakup event, with the Monte Carlo model calculations was made. The constructed Monte Carlo model described quite satisfactory the total momentum and transverse momentum distributions of [Formula: see text]-particles and the distribution of angles between the total momentum (as well as transverse momentum) vectors of two [Formula: see text]-particles in 9Be* nucleus breakup events in experiment. For the first time, the total momentum and transverse momentum distributions of neutrons, accompanying two [Formula: see text]-particles from 9Be* decay, in peripheral interactions of 9Be nuclei with emulsion nuclei were reconstructed using the Monte Carlo model.

By the methods of mathematical statistics we test a qualitative prediction of the old theory of relativistic hy-drodynamics non-viscous liquid which can be used as a part of the process of hadronization within the modern hydrody-namical approach for the description of the quark-gluon plasma. Experimental data on the interaction of protons with the energies of 0.8 TeV with emulsion nuclei are used. Results do not contradict the formation of relativistic ideal non-viscous liquid in rare central collisions.

It is shown that in central collisions of $^{197}$Au nuclei with heavy emulsion nuclei at 11.6 $A$GeV/c two-particles pseudorapidity correlations for produced particles in terms of correlation functions demonstate predominantly long-range behaviour in contrast to nucleon-nucleon interactions. The experimental data are compared with calculations based on the FRITIOF-M model and the model of independent emission of particles.