The transverse momentum distribution and the transverse mass distribution of charged hadrons produced in nucleus-nucleus collisions at high energies are described by using a two-cylinder model. The results calculated by the model are compared and found to be in agreement with the experimental data of the STAR and E895 Collaborations,measured in Au-Au collisions at the relativistic heavy ion collider (RHIC) and alternating-gradient synchrotron (AGS) energies,respectively. In the energy range concerned,the excitation degree of emission source close to the central axis of cylinders increases obviously with the collision centrality and incident energy increasing,but it does not show any obvious change with the increase of the (pseudo)rapidity in central collisions. The excitation degree of emission source close to the side-surface of cylinders does not show any obvious change with the collision centrality,the (pseudo)rapidity,and the incident energy increasing.
A study of intermittency of target associated fragments produced in the interactions of ^(16)O- AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F_q,has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variableχ(z)suggested by Bialas and Gazdzicki.The anomalous dimensions, d_q,increase linearly with the order of moments,q.This observation indicates the association of multifractility with production mechanism of target associated fragments.
Angular distributions of pions and kaons produced in heavy ion collisions at the low-energy end of high energies (1-2 A GeV) have been investigated by using a multisource ideal gas model.The model covers the expansions and movements of the emission sources,and it is related to the collective flows.By using the analytic expression and the Monte Carlo method,the azimuthal and polar angle distributions of mesons are calculated by the model and compared with the experimental data of the KaoS Collaboration.
