Justification of Landau Hydrodynamic-Tube Model in Central Relativistic Heavy-Ion Collisions

The statistical event-by-event analysis of inelastic interactions of 16O and 32S nuclei in emulsion at 60 A GeV/c and 200 A GeV/c reveals the existence of groups of high multiplicity events belonging to very central nuclear interactions with Gaussian pseudorapidity distributions for produced particles as suggested by the original hydrodynamic-tube model. Characteristics of these events are presented. The experimental observations are interpreted as a result of quark-gluon plasma formation in the course of central nuclear interactions.