High-pT Charged-Hadron Suppression in Au + Au Collisions at √sNN = 200 GeV.

The PHENIX experiment at RHIC has measured charged hadron yields at mid-rapidity over a wide range of transverse momentum    (0.5 < pT < 10 GeV/c) in Au + Au collisions at √sNN = 200 GeV. For both charged hadrons and neutral pions, the yields per nucleon-nucleon collision are significantly suppressed in central collisions compared to both peripheral and nucleon-nucleon collisions. The suppression sets in gradually and increases with increasing centrality of the collisions.                                                                          

The measured centrality dependence of suppression of hadron yield, suppression of back-to-back correlation and azimuthal anisotropy all imply a strong dependence on the underlying collision geometry.We present a simple model of jet absorption in dense matter which incorporates a realistic nuclear geometry. This model describes quantitatively the observed suppression of the high pT hadron yield and of the back-to-back angular correlations.