Transverse momentum dependence in gluon distribution and fragmentation functions

Abstract

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

Azimuthal and single spin asymmetries in hard scattering processes

“…Similarly, there exists an analogue of the quark transversity distribution, involving again linearly polarized gluons. A more detailed comparison with the corresponding notation of the Amsterdam group [220] can be found in Appendix C of Ref. [135] (see also Ref.…”

Rapidity evolution of gluon TMD from low to moderate x

“…Matrix elements of this operator between unpolarized hadrons can be parametrized as [6] d 2 z ⊥ e i(k,z) ⊥ p|F aη i (β B , z ⊥ )F aη j (β B , 0 ⊥ )|p + ξp 2 = 2π 2 δ(ξ)β B g 2 R ij (β B , k ⊥ ; η)…”

Gluonic pole cross sections and single spin asymmetries in hadron-hadron scattering

“…Following the treatment of TMD functions in Ref. [21] we take for the Γ ∂ (x) and the gluonic pole matrix elements the parametrizations…”