Reconstructing the Freeze-out State in Pb+Pb Collisions at 158 AGeV/c
Abstract
For a class of analytical parametrizations of the freeze-out state of relativistic heavy ion collisions, we perform a simultaneous analysis of the single-particle m_t-spectra and two-particle Bose-Einstein correlations measured in central Pb+Pb collisions at the CERN SPS. The analysis includes a full model parameter scan with chi^2 confidence levels. A comparison of different transverse density profiles for the particle emission region allows for a quantitative discussion of possible model dependencies of the results. Our fit results suggest a low thermal freeze-out temperature T approximately 95 +- 15 MeV and a large average transverse flow velocity of about 0.55c +- 0.07c. Moreover, the fit favours a box-shaped transverse density profile over a Gaussian one. We discuss the origins and the consequences of these results in detail. In order to reproduce the measured pion multiplicity our model requires a positive pion chemical potential. A study of the pion phase-space density indicates \mu_\pi approximately 60 MeV for T = 100 MeV.
Keywords
Cite
@article{arxiv.nucl-th/9907096,
title = {Reconstructing the Freeze-out State in Pb+Pb Collisions at 158 AGeV/c},
author = {Boris Tomasik and Urs Achim Wiedemann and Ulrich Heinz},
journal= {arXiv preprint arXiv:nucl-th/9907096},
year = {2009}
}
Comments
20 pages, 16 figures included via epsf, RevTeX, needs bbox.sty (provided)