Freeze out in narrow and wide layers

Abstract

The freeze out of particles from a layer of finite thickness is discussed in a phenomenological kinetic model. The proposed model, based on the Modified Boltzman Transport Equation, is Lorentz invariant and can be applied equally well for the freeze out layers with space-like and time-like normal vectors. It leads to non-equilibrated post freeze out distributions. The dependence of the resulting distribution on the thickness of the layer is presented and discussed for a space-like freeze out scenario.

Comments: Minor corrections to improve the presentation. 4 pages, 2 figures, to appear in the Proceedings of "Quark Matter 2005", August 4-9, 2005, Budapest, Hungary