W and Z transverse momentum distributions : resummation in q T - space

We describe an alternative approach to the prediction of W and Z transverse momentum distributions based on an extended version of the DDT formula. The resummation of large logarithms, mandatory at small qT, is performed in qT-space, rather than in the impact parameter b. The leading, next-to-leading and nextto-next-to-leading towers of logarithms are identical in the b-space and qT-space approaches. We argue that these terms are sufficient for W and Z production in the region in which perturbation theory can be trusted. Direct resummation in qT-space provides a unified description of vector boson transverse momentum distributions valid at both large and small qT.