4th EGEE User Forum/OGF 25 and OGF Europe's 2nd International Event

Theoretical studies of Heavy ion collisions using the EGEE Grid infrastructure

3 Mar 2009, 18:00

5m

Foyer (Le Ciminiere, Catania, Sicily, Italy)

Poster Scientific results obtained using grid technology Poster session

Speaker

Mrs Vaia Prassa (Aristotle University of Thessaloniki)

Description

The knowledge of the properties of highly compressed and heated hadronic matter is an important issue for the understanding of astrophysical processes, such as the mechanism of supernovae explosions and the physics of neutron stars. Heavy Ion Collisions (HIC) provides the unique opportunity to explore highly excited hadronic matter under controlled conditions (high baryon energy densities and temperatures) in the laboratory.

Detailed analysis

We have investigated the role of kaon potentials and in particular their explicit isospin dependence on the production of kaons in intermediate energy heavy ion collisions within a covariant transport equation of a Boltzmann type. The kaon potentials have been evaluated in two schemes, one following a Chiral Perturbation approach and a second one within the framework of an Effective Field picture, which is more consistent with the corresponding baryonic mean-field. The numerical solution of this transport equation is performed within the framework of a statistical model, which requires massive amounts of time-consuming calculations. The EGEE Infrastructure has offered us the possibility to perform these calculations in less than the 1/40th of the time needed previously. Here we present some of the results obtained, the problems encountered during the last four years using the Grid infrastructure and the solutions given to overcome them.

Keywords

Asymmetric nuclear matter, relativistic heavy ion collisions, strangeness production

Impact

Our studies have shown a reduction of the kaon yields when the kaon potentials are used, as expected due to their repulsive nature. The theoretical results are in very good agreement with the experimental data in collisions between light and heavy nuclei. We have focussed our attention on the K0/K+ yield ratio, recently suggested as a good probe of the isovector part of the EoS at high densities. For the case of the ChPT potential, the ratio is particularly changing as we pass to stiffer parameterisations of the equation of state, towards a larger K0 production, as a result of this competition. However, in the OBE scheme this effect is less evident due to the moderate density dependence of the isospin part of the kaon potential.

Conclusions and Future Work

As an important result the kaon potential only moderately influences the strangeness ratio indicating the robusteness of this observable in determining the isospin part of the nuclear EoS.
In our future work we intend to go to higher energies and baryon densities. This is motivated by the new experimental facilities (FAIR, GSI), where signatures for new physics is expected to be revealed from a possible phase transition at high densities in neutron rich systems.

URL for further information

http://www.physics.auth.gr/en/research_activity/index/2