Nucleon parton distributions at low normalization point in the large Nc limit

Diakonov, Dmitri; Петров, В. А.; Pobylitsa, P. V.; Polyakov, Maxim V.; Weiss, C.

doi:10.1016/s0550-3213(96)00486-5

Cited by 233 publications

(413 citation statements)

References 31 publications

Supporting

Mentioning

387

Contrasting

Order By: Relevance

“…the unexpectedly small quark spin fraction of the nucleon, can be explained at least qualitatively with no need of a large gluon polarization at the low renormalization scale [5], [19]. Finally, the model predicts a sizably large isospin asymmetry also for the spin-dependent sea-quark distributions, which we expect will be confirmed by near future experiments [10], [13], [18], [20].…”

Section: Introductionsupporting

confidence: 74%

“…Among others, most important in the above-explained context is its field theoretical nature, i.e. the proper account of the polarization of Dirac sea quarks, which enables us to make reasonable estimation not only of quark distributions but also of antiquark distributions [10]- [13]. It has already been shown that, without introducing any adjustable parameter, except for the initial-energy scale of the Q 2 -evolution, the CQSM can describe nearly all the qualitatively noticeable features of the recent high-energy deep-inelastic scattering observables.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model. I. Phenomenological predictions

Wakamatsu

2003

Phys. Rev. D

View full text Add to dashboard Cite

Theoretical predictions are given for the light-flavor sea-quark distributions in the nucleon including the strange quark ones on the basis of the flavor SU(3) version of the chiral quark soliton model. Careful account is taken of the SU(3) symmetry breaking effects due to the mass difference ∆m s between the strange and nonstrange quarks, which is the only one parameter necessary for the flavor SU(3) generalization of the model. A particular emphasis of study is put on the light-flavor

show abstract

Section: Introductionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model. I. Phenomenological predictions

Wakamatsu

2003

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…The χQSM has been derived from the instanton model of the QCD vacuum [16]. Due to the field-theoretical nature of the χQSM, the quark and antiquark distribution functions computed in the model satisfy all general QCD requirements (positivity, sum rules, inequalities) [17]. The model results for the known distribution functions -f q 1 (x), fq 1 (x) and g q 1 (x) -agree within (10 -30)% with phenomenological parameterizations [18].…”

Section: Ingredients For Prediction: H ⊥ 1 and H A 1 (X)mentioning

confidence: 99%

Predictions for azimuthal asymmetries in pion and kaon production in SIDIS off a longitudinally polarized deuterium target at HERMES

2002

View full text Add to dashboard Cite

Predictions are made for azimuthal asymmetries in pion and kaon production from SIDIS off a longitudinally polarized deuterium target for HERMES kinematics, based on information on the 'Collins fragmentation function' from DELPHI data and on predictions for the transversity distribution function from non-perturbative calculations in the chiral quark-soliton model. There are no free parameters in the approach, which has been already successfully applied to explain the azimuthal asymmetries from SIDIS off polarized proton targets observed by HERMES and SMC.

show abstract

“…These inequalities hold for each quark flavor f . In the leading order of the large N c limit we have for the u and d distribution functions of the proton [10,11]:Therefore the set of usual inequalities (1) takes the following form in the large N c limit(large N c old bounds) (3) Note that in the last inequality (3) we have the absolute value of ∆ L q u in contrast to Soffer inequality at finite N c (1). Actually we combined two Soffer inequalities for f = u, d (1) and we made use of the large N c relation ∆ L q u = −∆ L q d (see eq.…”

mentioning

confidence: 99%

“…These inequalities hold for each quark flavor f . In the leading order of the large N c limit we have for the u and d distribution functions of the proton [10,11]:…”

mentioning

confidence: 99%

New positivity bounds on polarized parton distributions in multicolored QCD

Pobylitsa

Polyakov

2000

Phys. Rev. D

View full text Add to dashboard Cite

We derive new positivity bounds on spin-dependent parton distributions in multicolored QCD. They are stronger than Soffer inequality. We check that the new inequalities are stable under one-loop DGLAP evolution to higher normalization points.1. In spite of the vast phenomenological data providing information about the quark and gluon distributions in nucleons we are still far from the complete knowledge of all twist-two distributions, especially of the spindependent ones. Therefore various positivity bounds on parton distributions are very helpful. In particular, an important role is played by Soffer inequality [1] that constraints the transversity quark distribution which is not measured yet. At first sight the set of already known positivity bounds for twist-two distributions is complete and no enhancement can be derived on general grounds without solving the dynamics of QCD. However, if one takes QCD in the limit of large number of colors N c then it is possible to obtain new stronger inequalities.It is well known that in the large N c limit [2] the baryons are described by mean field (Hartree) equations [3], which can be written in terms of bilocal meson fields with all possible spin and isospin quantum numbers. Although the corresponding effective bilocal meson action is not known, a number of results have been obtained for the large N c baryons without specifying the dynamics. Usually these results use the spin-flavor symmetry [4,5] of the solution of the Hartree equation describing the nucleon and ∆ resonance: this solution is invariant under simultaneous space, spin and isospin rotations (but not invariant under a pure flavor rotation). Owing to this spin-flavor symmetry the baryon states (described by this mean field solution) appear as "rotational excitations" with spin S and isospin T connected by constraint S = T [4,5]. In particular, this approach allows to describe nucleon (S = T = 1/2) and ∆ resonance (S = T = 3/2).This picture of the large N c baryons is extensively used in the Skyrme model [6,7] and various chiral quarksoliton models [8]. But some general model-independent results have been extracted for the large N c baryons using only the spin-flavor symmetry [9]. This includes, for example, the identities for the mass splitting of baryons and the large N c classification of spin and isospin structures of various form factors. In this paper we study quark distribution functions relying only on the large N c limit and on the spin-flavor symmetry of the large N c mean field solution.We first present our main result -the new positivity bounds which can be considered as a serious enhancement of the Soffer inequality and then give the derivation and check the stability of the bounds under one-loop the DGLAP evolution.2. Let us first formulate the new positivity bound. At finite number of QCD colors the unpolarized (q f ), longitudinal polarized (∆ L q f ) and transverse polarized (∆ T q f ) quark (antiquark) distributions are known to be constrained by the following set of inequalitiesThe last ineq...

show abstract

Nucleon parton distributions at low normalization point in the large Nc limit

Cited by 233 publications

References 31 publications

Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model. I. Phenomenological predictions

Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model. I. Phenomenological predictions

Predictions for azimuthal asymmetries in pion and kaon production in SIDIS off a longitudinally polarized deuterium target at HERMES

New positivity bounds on polarized parton distributions in multicolored QCD

Contact Info

Product

Resources

About