CENTRALITY DEPENDENCE OF NUCLEAR MODIFICATION FACTOR IN Au+Au COLLISIONS AT $\sqrt{s_{NN}}=200~{\rm GeV}$

Centrality dependence of nuclear modification factor at high pT above 4 GeV /c is studied in nucleus–nucleus collisions at [Formula: see text]. We find that the centrality dependence of the nuclear modification factor can be factorized as a Boltzmann function F(b). Comparing our model calculation with PHENIX data, we further confirm that the high pT spectrum of particles is dominated by surface emission.