Recombination plus fragmentation model at RHIC

We discuss the hadron production in relativistic heavy ion collisions. In
this model at intermediate transverse momentum Pt hadrons are produced by
recombination mechanism and at high Pt the hadrons are formed by
fragmentation of partons. By this model we understand comprehensively a
number of experimental data such as hadron spectra, ratios of hadron yield,
nuclear suppression factors and elliptic flow v2 as a function of transverse
momentum. Especially a valence quark number scaling law in experimental data
of elliptic flow strongly suggests the validity of recombination plus
fragmentation model.