Transverse momentum distributions in low-mass Drell-Yan lepton pair production at NNLO QCD

Abstract: The production of lepton pairs at low invariant mass and finite transverse momentum resolves QCD dynamics at the boundary between the perturbative and non-perturbative domains. We investigate the impact of NNLO QCD corrections on these observables at energies corresponding to the BNL RHIC collider and to fixed-target experiments. Satisfactory perturbative convergence is observed in both cases. Only the collider data are found to be well-described by perturbative QCD, thus indicating the importance of non-perturbative effects in lepton-pair transverse momentum distributions at fixed target energies.