Suppression of high transverse momentum hadrons at RHIC by (pre-) hadronic final state interactions

Abstract

We investigate transverse hadron spectra from proton+proton, deuteron+Au and Au+Au collisions at sqrt{s}=200 GeV and 17.3 GeV within the Hadron-String-Dynamics (HSD) approach which is based on quark, diquark, string and hadronic degrees of freedom as well as Pythia calculations for the high pT spectra. The comparison to experimental data on transverse mass spectra from p+p, d+Au and Au+Au reactions shows that pre-hadronic effects are responsible for both the hardening of the spectra for low transverse momenta (Cronin effect) as well as the suppression of high pT hadrons. The interactions of formed hadrons are found to be negligible in central Au+Au collisions at sqrt{s}=200 GeV for pT\geq 6 GeV/c, but have some importance for the shape of the ratio R_{AA} at lower pT values (\leq 6 GeV/c). The large suppression seen experimentally is attributed to the inelastic interactions of 'leading' pre-hadrons with the dense environment, which could be partly of colored partonic nature in order to explain the large attenuation seen in most central Au+Au collisions.