Extracting Nucleon Strange and Anapole Form Factors from World Data

Young, R.; Roche, J.; Carlini, R.; Thomas, A. W.

doi:10.1103/physrevlett.97.102002

Cited by 133 publications

(139 citation statements)

References 30 publications

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“…Finally, strange chiral loops can also lead to nonzero values for strange electric and magnetic form factors [36]. The magnitude of the kaon cloud contributions, although rather small, is consistent with that of the available data [37].…”

Section: Resultssupporting

confidence: 70%

Pion cloud and the sea of the nucleon

Melnitchouk

2009

Indian J Phys

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Section: Resultssupporting

confidence: 70%

Pion cloud and the sea of the nucleon

Melnitchouk

2009

Indian J Phys

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“…Our treatment is similar to that of Ref. [36], but utilizes all available low Q 2 data including the recent HAPPEX results [22,23] and incorporates the uncertainties in the electromagnetic and axial form factors. We find that the agreement among different measurements is good and we obtain fits with acceptable χ 2 .…”

Section: Discussionmentioning

confidence: 99%

Global analysis of nucleon strange form factors at lowQ2

2007

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We perform a global analysis of all recent experimental data from elastic parity-violating electron scattering at low Q 2 . The values of the electric and magnetic strange form factors of the nucleon are determined at Q 2 = 0.1 GeV/c 2 to be G s E = −0.008 ± 0.016 and G s M = 0.29 ± 0.21.DOI: 10.1103/PhysRevC.76.025202 PACS number(s): 11.30. Er, 13.40.Gp, 13.60.Fz The existence of a "sea" of quarks and antiquarks in the nucleon has been firmly established in deep-inelastic lepton scattering experiments as well as in the production of dilepton pairs (the Drell-Yan process). However, demonstrating the role of theseqq pairs in the static electromagnetic properties of the nucleon has been a more elusive and difficult task.As the lightest quark that contributes only to the qq sea, the strange quark provides a unique window on the role of the sea in the nucleon's electromagnetic structure. As suggested by Kaplan and Manohar [1], knowledge of neutral current form factors, when combined with electromagnetic form factors, provides access to the contribution of strange quarks to these form factors. At low momentum transfers, the neutral current form factors can be determined through parity-violating (PV) electron scattering experiments [2,3].During the last decade, there has been dramatic progress in the study of the strange quark-antiquark contributions to the nucleon elastic electromagnetic form factors. A series of definitive PV electron scattering experiments along with several theoretical studies now provides a basis for extracting precision information on these strange quark contributions. In this work we report the results of a global analysis of all these experiments, including both the latest data obtained in experiments performed at the Jefferson Laboratory and the appropriate theoretical input on radiative corrections, and obtain values for the strange electric and magnetic form factors of the nucleon at a four-momentum transfer Q 2 = 0.1 GeV/c 2 . We have also studied the sub-leading Q 2 dependence of these two form factors and found that so far the data do not provide conclusive information. I. STRANGE FORM FACTORS AND PARITY-VIOLATING ELECTRON SCATTERINGThe nucleon vector strange form factors, G s E and G s M , characterize the contribution of the strange sea quarks to the nucleon electromagnetic form factors, and thereby their contribution to the charge and magnetization distributions in the nucleon. where A nvs is the "non-vector-strange" asymmetry (independent of G s E and G s M ) and η E and η M are functions of kinematic quantities, nucleon electromagnetic form factors, and nuclear models (for nonhydrogen targets).For elastic e-p scattering, the full form of the asymmetry is [4]where M p is the mass of the proton and θ is the electron scattering angle. In Eq. (2), G F and α are the Fermi and fine structure constants, respectively. Q 2 is the four-momentum transfer. G (p,n) E,M are the proton and neutron electric and magnetic form factors, while G e A is the proton axial form factor seen by an elec...

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“…We see that the investigation of the elastic NC neutrino-nucleon scattering gives the opportunity to explore the nucleon strangeness [24,25] (mainly the axial strange part). The strangeness of the nucleon is also investigated in the elastic ep scattering [15,26,27]. The extraction of this contribution is sensitive to the accuracy of the EM form-factors.…”

Section: Jhep09(2010)053mentioning

confidence: 99%

Neural network parameterizations of electromagnetic nucleon form-factors

Graczyk

Płoński

Sulej

2010

J. High Energ. Phys.

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Abstract:The electromagnetic nucleon form-factors data are studied with artificial feed forward neural networks. As a result the unbiased model-independent form-factor parametrizations are evaluated together with uncertainties. The Bayesian approach for the neural networks is adapted for χ 2 error-like function and applied to the data analysis. The sequence of the feed forward neural networks with one hidden layer of units is considered. The given neural network represents a particular form-factor parametrization. The so-called evidence (the measure of how much the data favor given statistical model) is computed with the Bayesian framework and it is used to determine the best form factor parametrization.

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Extracting Nucleon Strange and Anapole Form Factors from World Data

Cited by 133 publications

References 30 publications

Pion cloud and the sea of the nucleon

Pion cloud and the sea of the nucleon

Global analysis of nucleon strange form factors at lowQ2

Neural network parameterizations of electromagnetic nucleon form-factors

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