The strange quark contribution to the proton's magnetic moment

Spayde, D. T.; Beck, D.; Hasty, R.; Averett, T.; Barkhuff, D.; Dodson, G.; Dow, K.; Farkhondeh, M.; Franklin, Wilbur A.; Tsentalovich, E.; Yang, Bojun; Zwart, T.; Beise, E. J.; Breuer, H.; Tieulent, R.; Carr, R.; Covrig, S.; Filippone, B. W.; Ito, T. M.; McKeown, R. D.; Korsch, W.; Kowalski, S.; Mueller, B.; Pitt, M. L.; Ramsey-Musolf, Michael J.; Ritter, J.; Wells, S. P.

doi:10.1016/j.physletb.2004.01.002

Cited by 215 publications

(154 citation statements)

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“…The results of measuring this asymmetry in the early experiments at the SLAC National Accelerator Laboratory led to the correct description of neutral weak interactions well before the discovery of the Z boson at CERN and provided a measurement of the weak mixing angle sin 2 θ W . Since then parity-violating electron scattering from various targets was studied at JLab [4][5][6][7], MIT/Bates [8,9], Mainz [10,11], and SLAC [12] as a tool for probing physics beyond the SM and hadronic structure. Currently, an active program is underway at JLab to continue these studies with a new level of precision.…”

Section: Introductionmentioning

confidence: 99%

Examination of higher-order twist contributions in parity-violating deep-inelastic electron-deuteron scattering

2010

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We show that parity-violating deep-inelastic scattering (PVDIS) of longitudinally polarized electrons from deuterium can in principle be a relatively clean probe of higher twist quark-quark correlations beyond the parton model. As first observed by Bjorken and Wolfenstein, the dominant contribution to the electron polarization asymmetry, proportional to the axial vector electron coupling, receives corrections at twist four from the matrix element of a single four-quark operator. We reformulate the Bjorken-Wolfenstein argument in a matter suitable for the interpretation of experiments planned at the Thomas Jefferson National Accelerator Facility (JLab). In particular, we observe that because the contribution of the relevant twist-four operator satisfies the CallanGross relation, the ratio of parity-violating longitudinal and transverse cross sections, R γ Z , is identical to that for purely electromagnetic scattering, R γ , up to perturbative and power-suppressed contributions. This result simplifies the interpretation of the asymmetry in terms of other possible novel hadronic and electroweak contributions. We use the results of MIT Bag Model calculations to estimate contributions of the relevant twist-four operator to the leading term in the asymmetry as a function of Bjorken x and Q 2 . We compare these estimates with possible leading twist corrections from violation of charge symmetry in the parton distribution functions.

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Section: Introductionmentioning

confidence: 99%

Examination of higher-order twist contributions in parity-violating deep-inelastic electron-deuteron scattering

2010

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“…Exposing the role of the strange quark via these measurements provides direct information on the underlying dynamics of nonperturbative QCD-a considerable achievement both experimentally and theoretically. The most precise separation of the strange electric and magnetic form factors is available at Q 2 ' 0:1 GeV 2 , where experiments by the SAMPLE [1,2], PVA4 [3], and HAPPEx [4,5] collaborations have been performed with varying kinematics and targets. At higher Q 2 , HAPPEx [6,7], PVA4 [8], and the forward angle G0 experiment [9] provide further information over the range Q 2 0:12-1:0 GeV 2 .…”

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confidence: 99%

“…The majority of measurements have been performed on hydrogen: SAMPLE [2,12], HAPPEx [5,6], PVA4 [3,8], and G0 [9].…”

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confidence: 99%

Extracting Nucleon Strange and Anapole Form Factors from World Data

et al. 2006

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The complete world set of parity violating electron scattering data up to Q 2 ∼ 0.3 GeV 2 is analysed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron, at Q 2 = 0.1 GeV 2 . Within experimental uncertainties, we find that the strange form factors are consistent with zero, as are the anapole contributions to the axial form factors. Nevertheless, the correlation between the strange and anapole contributions suggest that there is only a small probability that these form factors all vanish simultaneously.

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“…Experiments measuring the weak and electromagnetic form factors from the elastic scattering of electrons SAMPLE at MIT-Bates, G0 at JLab, PVA4 at MAMI and HAPPEX at JLab [2] have provided considerable insight on the role played by strange quarks in the charge, current and spin structure of the nucleon. Several interesting facts have also been revealed regarding the flavor structure of the sea quark content in the nucleon in the DIS experiments by the New Muon Collaboration (NMC) in 1991 [3], Fermilab E866 experiments [4], NA51 experiments [5] and HERMES [6].…”

Section: Introductionmentioning

confidence: 99%