Angular Dependence of the Nuclear Enhancement of Drell-Yan Pairs

نویسندگان

  • R. J. Fries
  • B. Müller
  • A. Schäfer
  • E. Stein
چکیده

We calculate the nuclear enhancement in the angular distribution of Drell-Yan pairs produced in proton–nucleus reactions. Nuclear effects are encoded in universal twist-4 parton correlation functions. We find that the Lam-Tung relation for the angular coefficients of the lepton-pair distribution holds for the double-hard, but not for the soft-hard contribution. We also predict that nuclear enhancement effects at RHIC energies can be large.

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تاریخ انتشار 1999