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.

Various aspects of the simple phenomenological model, the grand combinational model (GCM), proposed earlier for the systematic description of the center-of-mass (cm) rapidity distributions of different particles produced in high energy heavy ion collisions, were analyzed. The values of GCM parameters were extracted from fitting the cm rapidity distributions of the negative pions in 12 C+ 12 C collisions at √ snn = 3.14 GeV both in the experiment and using Modified FRITIOF Model. The GCM parameters extracted for the central 12 C+ 12 C collisions were compared with those obtained in central Pb+Pb collisions at super proton synchrotron (SPS) and alternating gradient synchrotron (AGS) energies between √ snn = 6.3 GeV and √ snn = 12.3 GeV and in central Au+Au collisions at Relativistic heavy ion collider (RHIC) energies between √ snn = 19.6 GeV and √ snn = 200 GeV. The plausible physical interpretations for the GCM parameters were given. The initial assumption that the parameter β of GCM should be zero for symmetric systems with identical colliding nuclei was validated. The parameter γ of GCM was deduced to follow an approximate asymptotic behavior (γ → 0 as √ snn → ∞) at very large cm energies, and γ ∼ = 0 could possibly be related to complete dehadronization of the whole collision system, along with attaining its maximum possible energy density, in central collisions of identical nuclei. The behavior of cm energy § Corresponding author. 1550049-1 Int. J. Mod. Phys. E 2015.24. Downloaded from www.worldscientific.com by UNIVERSITY OF IOWA on 09/11/16. For personal use only. Kh. K. Olimov et al.dependence of γ suggested that it could possibly be sensitive to deconfinement phase transition.

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In this paper, we have reported the transverse momentum ( p T ) spectra of averaged charged pions (π ± ), kaons (K ± ), protons and antiprotons in pp and most central 0-6% Au-Au collisions at √ s N N 200 GeV. The simulation is done by models including EPOS-LHC, EPOS-1.99, and QGSJETII-04. The transverse momentum ( p T ) distributions are plotted for π + + π − /2, (K + + K − )/2 and ( p + p)/2 in the p T range of 0 < p T < 3 GeV/c, 0 < p T < 2 GeV/c and 0.5 < p T < 4.5 GeV/c, respectively. We have also plotted the pseudo-rapidity distributions of charged hadrons produced in pp and Au-Au collisions at √ s N N 200 GeV.This analysis also includes the nuclear modification factor (R A A ) which is plotted as a function of p T to study the effects of deconfined medium created in most central Au-Au collisions. Simulation data are compared with the experimental data. The simulated distributions are compared to the RHIC experimental data at √ s N N 200 GeV for both collision systems in order to validate the above-mentioned simulation codes. Although it is observed that a good comparison exists between the models predictions and experimental data but none of them completely describe the experimental data over the entire p T and η range.