Collisional energy loss and the suppression of high $p_T$ hadrons
  We calculate nuclear suppression factor ($R_{AA}$) for light hadrons by taking only the elastic processes and argue that in the measured $p_T$ domain of RHIC, collisional rather than the radiative processes is the dominant mechanism for partonic energy loss. 
Jan-e Alam, Abhee K. Dutt-Mazumder and Pradip Roy