Pseudorapidity (rapidity) distribution of shower particles in relativisticnucleus-nucleus collisions

The pseudorapidity distributions of shower particles from the interactions accompanied by the emission of backward relativistic hadrons in nucleus-emu lsion collisions at Dubna energy have been studied by a thermalized cylinde r model. The wide distribution fitted by two Gaussian distributions and the narrow distribution fitted by one Gaussian distribution can be described b y the thermalized cylinder model. A Monte Carlo calculation shows that the thermalized cylinder model gives a good description of the statistical fluc tuations in experimental pseudorapidity distribution. The calculated result s are in agreement with the experimental data in the collisions of C, Ne an d Si with emulsion nuclei at incident momentum in the range (4.1-4.5)A GeV/ c. An isotropic emission fireball and a transverse or longitudinal flow are used to describe the rapidity distributions of charged particles produced in relativistic nucleus-nucleus collisions. A transverse flow is observed a t a lower energy (1A GeV) and a longitudinal flow is observed at a higher e nergy (200A GeV). Our Monte Carlo calculated results are in agreement with the experimental data of Au-Au collisions at 1A GeV, O-Au collisions at 60A and 200A GeV, S-S collisions at 200A GeV, and S-Ag collisions at 200A GeV.