A possible measurement of quark gluon plasma temperature in relativistic heavy ion collisions

Abstract

A possible measurement of the quark gluon plasma temperature is proposed, provided that this state of matter is accessible in relativistic heavy ion collisions. The idea is based on the observation that there are several di-vector-meson resonances produced in J/psi radiative decay and hadronic collisions (i.e. rho/sup 0/rho/sup 0/ resonance at 1.65 GeV in J/psi radiative decay, 2/sup + +/ phiphi resonance at 2.16 GeV and 2.31 GeV in pp collision at 400 GeV/c and ..pi..p collision at 100 GeV/c, and JJ enhancement at 7 GeV in ..pi..p collisions at 280 GeV/c and 150 GeV/c) which are believed to originate from 2 gluons due to the OZI forbidden nature of these reactions. Upon interpreting these resonances as 2/sup + +/ Q/sup 2 -/Q/sup 2/ states, the calculated masses, widths, the decay modes, and the hadronic production cross sections are all consistent with the experimental data. Since the hadronic production cross sections depend on the gluon distribution function, we may try to map out the gluon distribution function in the quark gluon plasma by measuring various di-vector-meson resonances, i.e. rhorho, ..omega..phi, K(K(, phiphi, D(D(, JJ, etc. at different energies in relativistic heavy ion collisions. The information on the temperature of themore » quark gluon plasma can be extracted if the gluon distribution function simulates that of a Bose gas. Several complications are briefly discussed.« less