09.11.2017: Implementarea etapelor II si III ale proiectului sunt in desfasurare.

"Predictions for anomal states and phase transitions in nuclear matter formed in relativistic collisions at CBM Experiment"

"Predictii pentru stari anomale si tranzitii de faza in materia nucleara formata in ciocniri nucleare relativiste la Experimentul CBM"-PREDICT@CBM"

Contract finantare nr. 09-FAIR/16.09.2016

Summary

In the context of the investigation of the phase diagram of the nuclear matter the aspects related to the transition order or transition type, as well as the position of the critical point for a given transition are the most important problems. The experimental results obtained by the 4 experiments from RHIC-BNL, as well as those obtained in experiments at SPS and LHC, ALICE Experiment, mainly, at CERN, indicated quark-gluon plasma formation and associated this transition with the almost perfect fluid flow when the critical temperature exceeds 170-190 MeV (Nucl.Phys.A757(2005)1-282, Nucl.Phys.A967(2017)1-1010, especially, 1-272). These results are related to the ultrarelativistic energies. The experiments from FAIR-GSI offer the possibility to perform collisions on an enough large energy scale, in laboratory system, using the same detector systems, conditions similar with those from RHIC-BNL, SPS and LHC-CERN, but at lower temperatures and larger baryonic chemical potentials and very high densities. The previous predictions, including ours, indicate a first order phase transition, and the critical point could be the point joining the first order phase transition curve with the second order phase transition region, the transition being continuously, at small baryonic chemical potential. Many results are related to the antiparticle to particle ratios. Therefore, in this stage of the project, we investigated some interesting physical quantities and their connections with the different phases of the nuclear matter. The main directions in this stage were the following: - Study of the particle production obtained in different relativistic nuclear collisions and thermodynamic equilibrium using Tsallis distribution. Connections with possible phases of hot and dense nuclear matter - Flow, nuclear matter jets and phases of nuclear matter at FAIR energies In this stage, an analysis of the particle transverse momentum spectra produced in relativistic nuclear collisions with the Tsallis distribution using different simulation codes (UrQMD, AMPT, GiBUU etc) has been done. The Tsallis parameters dependencies on the collision centrality, collision energy and rapidity have been investigated. Comparisons of the simulation code results with experimental results from nuclear collisions at similar energies (from RHIC-BES, mainly, but from GSI, JINR, CERN, too) have been done. The hydrodynamic behavior of the nuclear matter formed in the overlapping region of the two colliding nuclei seems to be the most adequate description of the collision dynamics. Also, many phases of the hot and dense nuclear matter seem to be related to this type of description. Therefore, in this stage of the project, the possible connections among flow and nuclear matter phases have been investigated. The formation of the nuclear matter jets has been analyzed. In this case the anti-kT jet detection algorithm with different cone radius was used. The study of Fourier anisotropic flow coefficients from the azimuthal distribution of the emitted particles completed this analysis. Connections with fireball evolution, from the initial formation moment up to the freeze-out were considered. Taking into account the energy range at the SIS-100 acceleration system, the results based on simulations can be compared with the experimental results obtained in symmetric collisions of light relativistic heavy ions (C-C at 4,5 A GeV/c, for example) or in deep asymmetric nucleus-nucleus collisions (He-Pb at 4,5 A GeV/c, for example) see the work C.Besliu et al (EPJ A1(1998)65-75) too, for a possible ordination in classes of equivalence, taking into account the cumulative production as an option for the transient regime in this energy range possible at FAIR-GSI. In the future, predictions on different phases of nuclear matter at FAIR energies, with special attention paid to the resonance matter formation and behavior of hadronic plasma will be included. Considering previous experimental results, as well as simulated data, some connections among processes in quarkonia region and cumulative effect will be investigated. All activities will be related to the improvements of the performances and handling of the YaPT (Yet another Physics Tool) system, partially done. All these will permit a good connection with CBM computing system and the introduction of the experiment geometry and structure, as well as of the performances of the detection systems.

Autoritatea Contractanta: Institutul de Fizica Atomica, Magurele
Contractor: Facultatea de Fizica, Universitatea din Bucuresti
Director de proiect: Prof.univ.dr. Alexandru JIPA
Durata: 36 luni
Echipa de cercetare


Etapa I an 2016
Etapa II an 2017
Etapa III an 2017

The role of the study of particle ratios in relativistic nuclear collisions. Previous experimental results and predictions for FAIR energies.
The study of the particle production obtained in different relativistic nuclear collisions and thermodynamic equilibrium using Tsallis distribution. Connections with possible phases of hot and dense nuclear matter.
Nuclear matter jets at FAIR energies .
A1.1 - Dynamic information based on the particle ratios. Systematic of experimental results obtained in different collisions at diverse energies. Analysis of different particle ratios produced in relativistic nuclear collisions using different simulation codes, at FAIR energies. Determination of the chemical freeze-out parameters (baryon chemical potential and chemical freeze-out temperature). Parameters dependence on the collision centrality, energy and rapidity will be investigated.
 AII.1 - Analysis of the particle transverse momentum spectra produced in relativistic nuclear collisions with the Tsallis distribution using different simulation codes (UrQMD, AMPT, GiBUU etc). Tsallis parameters dependencies on the collision centrality, collision energy and rapidity will be investigated. Comparisons of the simulation code results with experimental results from nuclear collisions at similar energies (from RHIC-BES, mainly, but from GSI, JINR, CERN, too)
AII.2 - Investigation of logarithmic oscillations in the simulated data/Tsallis fit ratio as a function of transverse momentum, pT, some connections with fractal structures, possible physical interpretations. Dependencies of these oscillations on collision centrality, collision type (A + A and p + p) and on the rapidity will be studied.

 AIII.1 -Nuclear matter jet analysis using anti-kT jet detection algorithm with different cone radius. The study of Fourier anisotropic flow coefficients from the azimuthal distribution of the emitted particles. Connections with fireball evolution.
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