NNLO corrections to massive lepton-pair production in longitudinally polarized proton-proton collisions

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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+ q → 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.