Origin of model relations among transverse-momentum dependent parton distributions

Abstract

Transverse-momentum dependent parton distributions (TMDs) are studied in the framework of quark models. In particular, quark-model relations among TMDs are reviewed, elucidating their physical origin in terms of the quark-spin structure in the nucleon. The formal aspects of the derivation of these relations are complemented with explicit examples, emphasizing how and to which extent the conditions which lead to relations among TMDs are implemented in different classes of quark models.

Relating transverse structure of various parton distributions

“…The above relations are consistent with the relations found in other models like [11] and are proven to be generic for scalar diquark models [27]. All the relations listed above are independent of the parameters in our model.…”

“…(3.3), (3.10) and (3.11), it is easy to see that 27) which was also observed in parton model [12] and is the generalization of the relation between the tensor charge (g q T ) and axial charge (g q A ) 28) found in many models and lattice QCD(see [12] and references therein). A non-linear relation is satisfied as…”

Transverse structure of a proton in a light-front quark-diquark model

“…The above relations are consistent with the relations found in other models like Bag model [10], LCCQM and are proved to be generic for diquark models [34]. Note that all the relations listed above are independent of the parameters of our model.…”

Revisiting model relations between T -odd transverse-momentum-dependent parton distributions and generalized parton distributions

“…A review of model-induced relations between different TMDs and between TMDs and GPDs can be found in Refs. [1,8,44].…”