title: Freeze-out problem in hydrokinetic approach to A + A collisions.
abstract: A new method for evaluating spectra and correlations in the hydrodynamic approach is proposed. It is based on an analysis of the Boltzmann equations (BE) in terms of probabilities for constituent particles to escape from the interacting system. The conditions of applicability of the Cooper-Frye freeze-out prescription are considered within the method. The results are illustrated with a nonrelativistic exact solution of BE for an expanding spherical fireball as well as with approximate solutions for ellipsoidally expanding ones.
authors.affiliation: Bogolyubov Institute for Theoretical Physics, Kiev 03143, Metrologichna 14b, Ukraine and IF-University of São Paulo, C.P. 66318, 05389-970 São Paulo, SP, Brazil.
authors.forename: Yu M
authors.initials: YM
authors.lastname: Sinyukov
authors.forename: S V
authors.initials: SV
authors.lastname: Akkelin
authors.forename: Y
authors.initials: Y
authors.lastname: Hama