Transverse momentum dependence in gluon distribution and fragmentation functions - art. no. 094021

We investigate the twist two gluon distribution functions for spin-1/2 hadr ons, emphasizing the intrinsic transverse momentum of the gluons. These fun ctions are relevant in leading order in the inverse hard scale in scatterin g processes such as inclusive leptoproduction or Drell-Yan scattering, or m ore generally in hard processes in which at least two hadrons are involved. They show up in azimuthal asymmetries. For future estimates of such observ ables, we discuss specific bounds on these functions.