Relativistic Diffusion Model and Analysis of Large Transverse Momentum Distributions

In order to describe large transverse momentum (pT) distributions observed in high energy nucleus-nucleus collisions, a stochastic model in the three dimensional rapidity space is introduced. The fundamental solution of the radial symmetric diffusion equation is Gaussian-like in radial rapidity. We can also derive a pT or radial rapidity distribution function, where a distribution of emission center is taken into account. The solution is applied to the analysis of observed large p T distributions of charged particles. It is shown that our model approaches to a power function of p T in the high transverse momentum limit