Energy loss of fast quarks in nuclei.
/ Authors
Mikkel B. Johnson, B. Kopeliovich, I. Potashnikova, P. McGaughey, J. Moss, J. Peng, G. Garvey, M. Leitch, M. Adams, D. Alde
and 15 more authors
H. Baer, M. Barlett, C. Brown, W. Cooper, T. Carey, G. Danner, G. Hoffmann, Y. Hsiung, D. Kaplan, A. Klein, C. Lee, J. Lillberg, R. Mccarthy, C. Mishra, M. Wang
/ Abstract
We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment.
Journal: Physical review letters