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An attempt to incorporate separate chemical and thermal freeze outs in hydrodynamics

N. Arbex·F. Grassi·Y. Hama·O. Socolowski Jr
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Abstract

From an analysis of various types of data obtained in relativistic nuclear collisions, the following picture has emerged in thermal and hydrodynamical descriptions: as the fluid expands and cools, particles first undergo a chemical freeze out at T_ch.~160-200 MeV then a thermal freeze out at T_th~100-140 MeV. In this paper we show how to incorporate these separate freeze outs consistently in a hydrodynamical code via a modified equation of state (general case) or via a modified Cooper-Frye formula (particular case of T_ch. close to T_th. or few particle species undergoing early chemical freeze-out). The modified equation of state causes faster cooling and may have sizable impact on the predicted values of observables.

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N. Arbex, F. Grassi, Y. Hama, O. Socolowski Jr. 2001-09-20. An attempt to incorporate separate chemical and thermal freeze outs in hydrodynamics. https://arxiv.org/abs/nucl-th/0102056

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