Covariant description of kinetic freeze out through a finite time-like layer

Abstract

The Freeze Out (FO) problem is addressed for a covariant FO probability and a finite FO layer with a time-like normal vector continuing the line of studies introduced in Ref. [1]. The resulting post FO momentum distribution functions are presented and discussed. We show that in general the post FO distributions are non-thermal and asymmetric distributions even for time-like FO situations.

Comments: 10 pages, 12 figures, major rewrite with changed content, corrected typos and new references added