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

Abstract

We present all the leading twist T-even TMDs in the light-front quark diquark model(LFQDM) and study the relations among them. The model contains both the scalar and vector diquark with the light front wave functions modeled from the soft-wall AdS/QCD prediction. The x − p 2 ⊥ factorization used in phenomenological extraction for TMDs is observed in this model. We present the results for the quark densities and the transverse shape of proton. The shape of the transversely polarized proton is shown to be non-spherical for nonzero transverse momentum. The scale evolution of both integrated and unintegrated TMDs are also presented in this paper.

Unified Description of Polarized and Unpolarized Quark Distributions in the Proton

“…This approach to color confinement provides effective semiclassical QCD bound-state equations [26][27][28][29], where the confinement potential is determined by an underlying superconformal algebraic structure [30][31][32]. Because of the increasing interest in parton distributions, LFHQCD-based models have been developed with modifications of the light-front wave functions [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Recently, we introduced a new approach for deriving PDFs as well as generalized parton distributions (GPDs) from LFHQCD [53] with minimal parameters.…”

Sivers and cos2ϕ asymmetries in semi-inclusive deep inelastic scattering in light-front holographic model

“…This relation is not expected to hold in models where the so-called lensing function does not factor out from the GPD in impart The light-front quark-diquark model [37] has been briefly discussed in the next section. The model has been used to investigate Wigner distributions, GPDs and T-even TMDs [38][39][40]. The model is also found to predict the single-spin asymmetries described by T-even TMDs (Collins asymmetries) quite accurately at different experimental scales [41].…”

“…In this model, the explicit form of the Sivers functions is given in Eq.16 and the unpolarized TMDs is given in [39]. The model result for Sivers asymmetries are shown in Fig.5 in the π + and π − channels and compared with the HERMES data [14] in the kinematical region 0.023 < x < 0.4, 0.2 < z < 0.7, 0.31 < y < 0.95, and P h⊥ > 0.05 GeV.…”

Working Group 1: Structure Functions and Parton Densities

“…5 (right), a ∆s + consistent with zero across the entire x range within fairly large uncertainties was found, in contrast to some earlier studies. In [45,46] a theoretical calculation of the transverse momentum dependent PDFs within the light-front quark di-quark model was presented. The resultant PDFs were found to be consistent with global fits, and were able to successfully describe the Collins asymmetry in semi-inclusive DIS.…”