The intrinsic transverse momentum of Drell-Yan pairs

A soft gluon summation technique is used in conjunction with a singular infrared behaviour of the QCD coupling constant to compute the moments of transverse momentum and of lepton pairs produced in hadron-hadron scattering. Remarkably, it is found that an α s which produces asymptotically linear Regge trajectories, gives the best account of for lepton pairs produced through valence quarks (and antiquarks), with no need of any intrinsic transverse momentum. Factorization of the cross section into its longitudinal and transverse momentum part is not assumed for the derivation of the mean values.