Linking generalized parton distributions to constituent quark models

Abstract

The link between the nucleon generalized parton distributions and the non-diagonal one-body density matrix in momentum space is studied. Attention is focussed on the region where quark generalized parton distributions (GPD's) describe emission and reabsorption of a single active quark by the target nucleon. The correct covariant connection with wave functions used in any constituent quark model is established. Results obtained with different constituent quark models are presented for the unpolarized quark GPD's.

Correlations in double parton distributions: perturbative and non-perturbative effects

“…The approach is particularly suitable for the description of Deep Inelastic Scattering (DIS) processes which find their natural environment in a LF-description. The numerous applications to a large varieties of DIS observables like polarized [24] and unpolarized [26][27][28] structure functions, spin and angular momentum distributions [29,30], helicity-independent and dependent GPDs [31][32][33], demonstrate the reliability and flexibility of the approach.…”

“…refs. [24,[31][32][33]) the considerations made for free canonical states can be generalized to interacting quarks in a proton, by means of a suitable representation of the Poincaré operators, namely the Bakamjian-Thomas construction [38]. The extension to interacting systems requires, in fact, a dynamical representation of the Poincaré group.…”

“…Since GPDs have been studied, precisely within the same LF-approach, by Pasquini, Boffi and Traini [31][32][33] some years ago, one can check directly the accuracy of eq. (2.18).…”

Helicity-dependent generalized parton distributions in constituent quark models

“…It is here obtained from the corresponding solution Ψ [c] λ ({ k i }, {λ i }, {τ i }) of the eigenvalue equation in the instant-form as described in Ref. [29]. Separating the spin-isospin component from the space part of the wave 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.…”