Parton distributions in the valon model

Hwa, Rudolph C.; Yang, C. B.

doi:10.1103/physrevc.66.025204

Cited by 118 publications

(254 citation statements)

References 21 publications

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“…It is worth noting some other non-perturbative studies of dPDFs in quark models for the nucleon, such as in the MIT bag [34] or in the constituent quark model model [35], also with the light-front wave functions [36,37]. We stress that the longitudinal correlation features in these models are qualitatively understood in the framework of the valon model [38,39], as shown in [40,41]. 2 The paper is organized as follows.…”

Section: Introductionmentioning

confidence: 98%

Double parton distribution of valence quarks in the pion in chiral quark models

Broniówski

Arriola

2020

Phys. Rev. D

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The valence double parton distribution of the pion is analyzed in the framework of chiral quark models, where in the chiral limit factorization between the longitudinal and transverse degrees of freedom occurs. This feature leads, at the quark-model scale, to a particularly simple distribution of the form D(x1, x2, y) = δ(1−x1 −x2)F (y), where x1,2 are the longitudinal momentum fractions carried the valence quark and antiquark, and y is the separation of their transverse positions. For y = 0 this result complies immediately to the Gaunt-Sterling sum rules. The DGLAP evolution to higher scales is carried out in terms of the Mellin moments. We then explore its role on the longitudinal correlation quantified with the ratio of the double distribution to the product of single distributions, D(x1, x2, y)/D(x1)D(x2). We point out that the ratios of moments x n 1 x m 2 / x n 1 x m 2 are independent of the evolution, providing particularly suitable measures to be tested in the upcoming lattice simulations. The transverse form factor F (y) is obtained in variants of the Nambu-Jona-Lasinio model with the spectral and Pauli-Villars regularizations. Interestingly, with the spectral regularization of the model, the effective cross section for the double parton scattering of pions is exactly equal to the geometric cross section, σ eff = π y 2 and yields about 20 mb.

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Section: Introductionmentioning

confidence: 98%

Double parton distribution of valence quarks in the pion in chiral quark models

Broniówski

Arriola

2020

Phys. Rev. D

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“…We consider the cases α = 0, 1/2, 1 and a = 1, 2. The first class corresponds to the so-called valon model [20,21] for the proton, which assumes…”

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confidence: 99%

Valence Double Parton Distributions of the Nucleon in a Simple Model

Broniowski

Arriola

2014

Few-Body Syst

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Valence double parton distribution functions of the nucleon are evaluated in the framework of a simple model, where the conservation of the longitudinal momentum is taken into account. The leading-order DGLAP QCD evolution from the low quark-model scale to higher renormalization scales is carried out via the Mellin moments of the distributions. Results of the valence quark correlation function show that in general the double distributions cannot be approximated as a product of the single-particle distributions.Theoretical interest in double parton distributions (dPDFs) in hadrons has been recently renewed (see the reviews [1,2] and the references therein). The activity is largely triggered by the experimental program at the LHC, where the double parton scattering (DPS) may bring substantial contribution in certain production processes [3,4]. Phenomenological aspects of the inclusion of the multi-parton effects have been widely pursued since the early days of the parton model [5], while many formal features of the multiparton evolution [6,7] follow from a pioneering study on fragmentation functions [8]. Elements of the QCD formulation are presented in [9][10][11][12], while a 2 GPD interpretation is provided in [13]. Positivity bounds for dPDFs were recently discussed in [14].Dynamic modeling of dPDFs has been up to now very little explored. In fact, the only calculations which nonperturbatively predict the valence dPDFs of the nucleon have been carried out in the framework of the MIT bag model [15] and in the constituent quark model [16]. In both calculations, the approximate implementation of relativity has the side effect of producing distributions with unphysical support, i.e., extending outside the interval 0 ≤ x 1 , x 2 , x 1 + x 2 ≤ 1. An important aspect of the dPDFs is that they allow to detect tight diquark correlations, in which case the dPDF becomes a function of the sum x 1 + x 2 . In the (x 1 , x 2 ) distribution plot the fingerprints are the straight-line structures inclined by 45 • .The purpose of this talk is to explore the valence dPDF of the proton in a very simple model which includes the exact momentum-conservation constraints and complies to the Lorentz invariance. Satisfaction of these requirements results in proper theoretical features, such as the correct support in the x-variables or the quarknumber and momentum sum rules [17]. In the considered model, the correlations between partons are due Talk presended by WB at the Light Cone 2013 Conference, Skiathos, Greece.

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“…Hwa about thirty years ago [2]. The model has been quite successful in describing a variety of hadronic phenomena [3,4]. In the polarized deep inelastic scattering domain, the model has successfully reproduced the existing data on g p,n,d 1 , and individual parton contributions, ∆q f (x, Q 2 ), to the nucleon spin, while predicting new results yet to be tested.…”

Section: Introductionmentioning

confidence: 89%

Contribution of orbital angular momentum to the nucleon spin

Momeni-Feili

Arash

Taghavi-Shahri

et al. 2017

Int. J. Mod. Phys. A

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Virtual parton excitations of proton achieve status of real particles after transition into the infinite momentum frame. In particular, QCD evolution of them should respect the conservation laws which in turn should be a necessary consequence of symmetry properties. I argue that these simple reasons may cast light on the so-called proton spin puzzle and upon an orbital momentum contribution of quarks and gluons to the proton spin. An already fulfilled experiment with a hint on possible observation of orbital excitations of gluons is pointed out.

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Parton distributions in the valon model

Cited by 118 publications

References 21 publications

Double parton distribution of valence quarks in the pion in chiral quark models

Double parton distribution of valence quarks in the pion in chiral quark models

Valence Double Parton Distributions of the Nucleon in a Simple Model

Contribution of orbital angular momentum to the nucleon spin

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