Transverse momentum dependent parton distributions in a light-cone quark model

Abstract

We review the information on the spin and orbital angular momentum structure of the nucleon encoded in the T-even transverse momentum dependent parton distributions within light-cone quark models. Model results for azimuthal spin asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering are discussed, showing a good agreement with available experimental data and providing predictions to be further tested by future CLAS, COMPASS and HERMES data.

Origin of model relations among transverse-momentum dependent parton distributions

“…[27]. Let us just mention that they were observed in the bag model [27,28], light-cone constituent quark models [20], some quark-diquark models [2,12,13], the covariant parton model [11] and more recently in the light-cone version of the chiral quark-soliton model [23]. Note however that there also exist models where the relations are not satisfied, like in some versions of the spectator model [26] and the quark-target model [30].…”

“…Â e z implies the two linear relations (19) and (20). The relation (44) is naturally also satisfied but is not independent.…”

“…[20] and the light-cone quark-diquark model (LCQDM) of Refs. [12,13,44] constitute the class of light-cone models; (ii) The covariant parton model of Ref.…”

Review of TMD Measurements

“…The distributions f ⊥ 1T and h ⊥ 1 are the imaginary parts and the g ⊥ 1T and h ⊥ 1L are the real parts of the interference terms between S and P wave components [3]. The chiral-odd h ⊥ 1T function is sensitive to the D-wave component [4]. The TMD f ⊥ 1T is known as the Sivers [5] function.…”

The multidimensional nucleon structure

“…In the following, we will show results from the light-front constituent quark model (LFCQM) [29], which has been extensively applied to calculate form factors [30], TMDs [31][32][33][34] and GPDs [35][36][37][38], showing a typical accuracy of 30%. Since our purpose is simply to illustrate the multipole structure, we computed only the naive T-even contributions in this model.…”