Energy loss of fast quarks in nuclei

Johnson, MB Kopeliovich, BZ Potashnikova, IK McGaughey, PL Moss, JM Peng, JC Garvey, GT Leitch, MJ Adams, MR Alde, DM Baer, HW Barlett, ML Brown, CN Cooper, WE Carey, TA Danner, G Hoffmann, GW Hsiung, YB Kaplan, DM Klein, A Lee, C Lillberg, JW McCarthy, RL Mishra, CS Wang, MJ

Mb. Johnson et al., Energy loss of fast quarks in nuclei, PHYS REV L, 86(20), 2001, pp. 4483-4487

29

INGLESE

Article

Physics

PHYSICAL REVIEW LETTERS

0031-9007 → ACNP

86

20

2001

4483 - 4487

ISI

0031-9007(20010514)86:20<4483:ELOFQI>2.0.ZU;2-M

We report an analysis of the nuclear dependence of the yield of Drell-Yan d imuons from the 800 GeV/c proton bombardment of H-2, C, Ca, Fe, and W targe ts. 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 l oss and shadowing on the nuclear-dependence ratios versus the incident prot on'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 nucle ar environment.