Abstract
We present spectra of charged hadrons from and collisions at measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central collisions at and evidence a strong suppression in the high region (). In contrast, the nuclear modification factor (at ) exhibits an enhancement of the high yields. These measurements indicate a high energy loss of the high particles in the medium created in the central collisions. The lack of suppression in collisions makes it unlikely that initial state effects can explain the suppression in the central collisions.
- Received 3 July 2003
DOI:https://doi.org/10.1103/PhysRevLett.91.072305
©2003 American Physical Society