  In the target rest frame and at high energies, Drell-Yan (DY) dilepton
production looks like bremsstrahlung of massive photons, rather than parton
annihilation. The projectile quark is decomposed into a series of Fock states.
Configurations with fixed transverse separations in impact parameter space are
interaction eigenstates for proton-proton (pp) scattering. The DY cross section
can then be expressed in terms of the same color dipole cross section as DIS.
We compare calculations in this dipole approach with E772 data and with
next-to-leading order parton model calculations. This approach is especially
suitable to describe nuclear effects, since it allows one to apply Glauber
multiple scattering theory. We go beyond the Glauber eikonal approximation by
taking into account transitions between states, which would be eigenstates for
a proton target. We calculate nuclear shadowing at large Feynman-x for DY in
proton-nucleus collisions and compare to E772 data. Nuclear effects on the
transverse momentum distribution are also investigated.
