Speakers
Dr
Hannah Petersen
(University of Frankfurt)
Marcus Bleicher
(Uni Frankfurt)
Description
A systematic study of HBT radii of pions, produced in heavy ion collisions in the intermediate energy regime (SPS), from an integrated (3+1)d Boltzmann+hydrodynamics approach is presented. The calculations in this hybrid approach, incorporating an hydrodynamic stage into the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) transport model, allow for a comparison of different equations of state (EoS) retaining the same initial conditions and final freeze-out. The results are also compared to the pure cascade transport model calculations in the context of the available data. Furthermore, the effect of different treatments of the hydrodynamic freeze-out procedure on the HBT radii are investigated. It is found that the HBT radii are essentially insensitive to the details of the freeze-out prescription as long as the final state interactions in the cascade are taken into account. The HBT radii $R_L$ and $R_O$ and the $R_O/R_S$ ratio are sensitive to the EoS that is employed during the hydrodynamic evolution. We conclude that the increased lifetime in case of a phase transition to a QGP (via a Bag Model equation of state) is not supported by the available data.
References:
Q.f. Li, J. Steinheimer, H. Petersen, M. Bleicher and H. Steocker,
``Effects of a phase transition on HBT correlations in an integrated Boltzmann+Hydrodynamics approach,''
arXiv:0812.0375 [nucl-th],
Physics Letters B (2009) in print
Author
Marcus Bleicher
(Uni Frankfurt)
