Role of the nonperturbative input in QCD resummed Drell-Yan Q(T) distributions - art. no. 114011

We analyze the role of the nonperturbative input in the Collins-Soper-Sterm an (CSS) b-space QCD resummation formalism for Drell-Yan transverse momentu m (Q(T)) distributions, and investigate the predictive power of the CSS for malism. We find that the predictive power of the CSS formalism has a strong dependence on the collision energy rootS in addition to its well-known Q(2 ) dependence, and the rootS dependence improves the predictive power at col lider energies. We show that a reliable extrapolation from perturbatively r esummed b-space distributions to the nonperturbative large b region is nece ssary to ensure the correct Q(T) distributions. By adding power corrections to the renormalization group equations in the CSS formalism, we derive a n ew extrapolation formalism. We demonstrate that at collider energies the CS S resummation formalism plus our extrapolation has an excellent predictive power for W and Z production at all transverse momenta Q(T)less than or equ al toQ. We also show that the b-space resummed Q(T) distributions provide a good description of Drell-Yan data at fixed target energies.