Universal Scaling of $p_T$ Distribution of Particles in Relativistic Nuclear Collisions

Abstract

With the experimental data from STAR, PHENIX and BRAHMS on the centrality and rapidity dependence of the $p_T$ spectrum in Au+Au and d+Au collisions, we show that there exists a scaling distribution which is independent of the colliding system, centrality and rapidity. The parameter for the average transverse momentum $<p_T>$ increases from peripheral to central d+Au collisions. This increase accounts for the enhancement of particle production in those collisions. A non-extensive entropy is used to derive the scaling function.