We consider QCD radiative corrections to the production of W and Z bosons in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. The calculation includes the γ-Z interference, finite-width effects, the leptonic decay of the vector bosons and the corresponding spin correlations. Our calculation is implemented in a parton level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state leptons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We show selected numerical results at the Tevatron and the LHC. March 2009The production of W and Z bosons in hadron collisions through the Drell-Yan (DY) mechanism [1] is extremely important for physics studies at hadron colliders. These processes have large production rates and offer clean experimental signatures, given the presence of at least one highp T lepton in the final state. Studies of the production of W bosons at the Tevatron lead to precise determinations of the W mass and width [2]. The DY process is also expected to provide standard candles for detector calibration during the first stage of the LHC running.Because of the above reasons, it is essential to have accurate theoretical predictions for the vector-boson production cross sections and the associated distributions. Theoretical predictions with high precisions demand detailed computations of radiative corrections. The QCD corrections to the total cross section [3] and to the rapidity distribution [4] of the vector boson are known up to the next-to-next-to-leading order (NNLO) in the strong coupling α S . The fully exclusive NNLO calculation, including the leptonic decay of the vector boson, has been completed more recently [5]. Full electroweak corrections at O(α) have been computed for both W [6] and Z production [7].In this Letter we present a new computation of the NNLO QCD corrections to vector boson production in hadron collisions. The calculation includes the γ-Z interference, finite-width effects, the leptonic decay of the vector bosons and the corresponding spin correlations. Our calculation parallels the one recently completed for Higgs boson production [8,9], and it is performed by using the same method.The evaluation of higher-order QCD corrections to hard-scattering processes is complicated by the presence of infrared (IR) singularities at intermediate stages of the calculation that prevents a straightforward implementation of numerical techniques. Despite this difficulty, general methods have been developed in the last two decades, which allow us to handle and cancel IR singularities [10,11,12] appearing in NLO QCD calculations. In the last few years, several research groups have been working on extensions of these methods to NNLO [13,14,15,16,17], and, recently, the NNLO calculation for e + e − → 3 jets wa...

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We consider QCD radiative corrections to the production of colourless high-mass systems in hadron collisions. The logarithmically-enhanced contributions at small transverse momentum are treated to all perturbative orders by a universal resummation formula that depends on a single process-dependent hard factor. We show that the hard factor is directly related to the all-order virtual amplitude of the corresponding partonic process. The direct relation is universal (process independent), and it is expressed by an all-order factorization formula that we explicitly evaluate up to the next-to-next-to-leading order (NNLO) in QCD perturbation theory. Once the NNLO scattering amplitude is available, the corresponding hard factor is directly determined: it controls NNLO contributions in resummed calculations at full nextto-next-to-leading logarithmic accuracy, and it can be used in applications of the q T subtraction formalism to perform fully-exclusive perturbative calculations up to NNLO. The universality structure of the hard factor and its explicit NNLO form are also extended to the related formalism of threshold resummation.