Gluon shadowing and hadron production at RHIC

Hadron multiplicity in the central rapidity region of high-energy heavy-ion collisions is investigated within a two-component mini-jet model which consists of soft and semi-hard particle production. The hard contribution from mini-jets is reevaluated using the latest parameterization of parton distributions and nuclear shadowing. The energy dependence of the experimental data from RHIC requires a strong nuclear shadowing of the gluon distribution in this model. The centrality dependence of the hadron multiplicity at s=130 GeV is reproduced well with the impact-parameter dependent parton shadowing. However, energy variation of the centrality dependence is needed to distinguish different particle production mechanisms such as the parton saturation model.