NNLO corrections to massive lepton-pair production in longitudinally polarized proton–proton collisions Original Research Article

We present the full next-to-next-to-leading order (NNLO) coefficient functions for the polarized cross section dΔσ/dQ for the Drell–Yan process p+p→l+l−+′X′. Here ′X′ denotes any inclusive hadronic state and Q represents the invariant mass of the lepton pair. All QCD partonic subprocesses have been included provided the lepton pair is created by a virtual photon, which is a valid approximation for Q<50 GeV. Unlike the differential distribution w.r.t. transverse momentum the dominant subprocess for the integrated cross section is given by q+q̄→γ∗+′X′ and its higher order corrections so that massive lepton pair production provides us with an excellent tool to measure the polarized anti-quark densities. Our calculations are carried out using the method of n-dimensional regularization by making a special choice for the γ5 matrix. We give predictions for double longitudinal spin asymmetry measurements at the RHIC.