Fermilab E866 has measured the target-mass dependence of Drell-Yan and J/ψ dimuon production induced by an 800 GeV proton beam on targets of Be, Fe and W. Clear evidence of nuclear shadowing is observed in the Drell-Yan cross section ratios per nucleon at small x2. The x1 dependence of the cross section ratios provides a determination of the energy loss of ultra-relativistic quarks as they pass through cold nuclei. Preliminary results for J/ψ yields show maximum cross section ratios that are slightly less than 1 at an xF value near 0.1. The yield on heavy targets is much more strongly suppressed relative to light targets at larger values of xF.
ASJC Scopus subject areas
- Nuclear and High Energy Physics