Azimuthal spin asymmetries in light-cone constituent quark models

Abstract

We present results for all leading-twist azimuthal spin asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering due to T-even transverse-momentum dependent parton distribution functions on the basis of a light-cone constituent quark model. Attention is paid to discuss the range of applicability of the model, especially with regard to the scale dependence of the observables and the transverse-momentum dependence of the distributions. We find good agreement with available experimental data and present predictions to be further tested by future CLAS, COMPASS and HERMES data.Comment: 23 pages, 14 figures, 1 tabl

Origin of model relations among transverse-momentum dependent parton distributions

“…In other words, the conditions 1-3 of Sec. III are satisfied in scalar diquark models with Yukawa-like vertex, and so are the TMD relations (19)- (21).…”

“…The conditions 1-3 of Sec. III are therefore satisfied in the covariant parton model, and so are the TMD relations (19)- (21). Since this model does not use the language of wave functions, the implementation of SUð6Þ spin-flavor symmetry is more delicate and one has to assume that the unpolarized and polarized distributions become simply proportional in order to recover the TMD relation (22).…”

GTMDs in Light-Cone Models

“…As a starting point, we used the χQSM and LFCQM which were introduced in Section 3 and already tested in the calculation of several nucleon observables [12,13,14,15,16]. In the case of F e 11 , both models give the same qualitative picture with a larger distribution amplitude when k ⊥ ⊥ b ⊥ and smaller when k ⊥ b ⊥ (see Fig.…”

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.…”