Results from Year-1 PHENIX (II) Particle multiplicity & ET vs. centrality [PRL 86, 3500 (2001)]

• Nch & ET increase faster than linearly with Npart: onset of hard processes (proportional to # binary inelastic colls.)

• Important constraint for particle production models:

  • "Soft + hard components" (HIJING) vs. gluon saturation (EKRT)

• <ET >/<Nch> ~ 0.8 GeV independent of centrality