2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82865It is shown that azimuthal asymmetry in transverse momentum distribution of particles observed in non-central heavy ion collisions can originate from pre-equilibrium rescattering. The phenomenon is studied using computer simulation of expanding pion gas created in Pb+Pb 160 GeV/n collisions. Results obtained are discussed in comparison with experimental results of NA49 collaboration. Theoretical understanding of mechanism generating the asymmetry is presented. Conclusion about non-equilibrium properties of the phenomenon studied is drawn.8 pages, TeX, 10 figures EPSNuclear Theorytext