Phenomenological analysis of rapidity distribution of negative pions in central C-12+C-12 collisions at root S-nn=3.14GeV

摘要

Various aspects of the simple phenomenological model, the grand combinational model (GCM), proposed earlier for the systematic description of the center-of-mass (cm) rapidity distributions of different particles produced in high energy heavy ion collisions, were analyzed. The values of GCM parameters were extracted from fitting the cm rapidity distributions of the negative pions in C-12+ C-12 collisions at root S-nn = 3.14 GeV both in the experiment and using Modified FRITIOF Model. The GCM parameters extracted for the central C-12+ C-12 collisions were compared with those obtained in central Pb + Pb collisions at super proton synchrotron (SPS) and alternating gradient synchrotron (AGS) energies between root S-nn = 6.3 GeV and root S-nn = (12).3 GeV and in central Au + Au collisions at Relativistic heavy ion collider (RHIC) energies between root S-nn = 19.6 GeV and root S-nn = 200 GeV. The plausible physical interpretations for the GCM parameters were given. The initial assumption that the parameter beta of GCM should be zero for symmetric systems with identical colliding nuclei was validated. The parameter gamma of GCM was deduced to follow an approximate asymptotic behavior (gamma -> 0 as root S-nn ->infinity) at very large cm energies, and gamma congruent to 0 could possibly be related to complete dehadronization of the whole collision system, along with attaining its maximum possible energy density, in central collisions of identical nuclei. The behavior of cm energy dependence of gamma suggested that it could possibly be sensitive to deconfinement phase transition.