Erratum: Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement [Phys. Rev. ST Accel. Beams<b>7</b>, 042802 (2004)]

Grames, Jospeh; Sinclair, C. K.; Mitchell, J. G.; Chudakov, E.; Fenker, H.; Freyberger, A.; Higinbotham, D. W.; Poelker, M.; Steigerwald, Michael L.; Tiefenback, M.; Cavata, C.; Escoffier, S.; Marie, F.; Pussieux, T.; Vernin, P.; Danagoulian, S.; Dharmawardane, V.; Fatemi, R.; Joo, K. S.; Zeier, M.; Gorbenko, V.; Nasseripour, R.; Raue, B. A.; Suleiman, R.; Zihlmann, B.

doi:10.1103/physrevstab.13.069901

Cited by 12 publications

(11 citation statements)

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“…We used polarized electron beams with currents up to I = 60 µA and energies of 359 and 684 MeV generated with a strained GaAs polarized source [16]. The average beam polarization, measured with Møller and Mott [17] polarimeters, was 85.8 ± 2.1(1.4)% at the lower (higher) incident energy. Helicity-correlated current changes were corrected with active feedback to about 0.3 parts-per-million (ppm).…”

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confidence: 99%

Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Androić¹,

Armstrong²,

Arvieux³

et al. 2010

Phys. Rev. Lett.

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137

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We have measured parity-violating asymmetries in elastic electron-proton and quasi-elastic electron-deuteron scattering at Q 2 = 0.22 and 0.63 GeV 2 . They are sensitive to strange quark contributions to currents in the nucleon, and to the nucleon axial current. The results indicate strange quark contributions of < ∼ 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial current at these four-momentum transfers.PACS numbers: 11.30. Er, 14.20.Dh, 25.30.Bf At short distance scales, bound systems of quarks have relatively simple properties and QCD is successfully described by perturbation theory. However, on the size scale of the bound state, ∼ 1 fm, the QCD coupling constant is large and the effects of the color fields are a significant challenge, even in lattice QCD. In addition to valence quarks, e.g., uud for the proton, there is a sea of gluons and qq pairs that plays an important role. From a series of experiments measuring the parity-violating asymmetries of electrons scattered from protons and neutrons, we can extract the contributions of strange quarks to nucleon ground state charge and magnetic form factors. These strange quark contributions are exclusively part of the quark sea because there are no strange valence quarks in the nucleon. experiments have previously reported measurements of these parity-violating asymmetries. Using the combined forward angle asymmetries and the SAMPLE backward angle proton and deuteron measurements, a complete experimental determination of the strange quark vector currents and the axial current (see discussion below) has been made at a four-momentum transfer Q 2 = 0.1 GeV 2 [5]. In this paper, we report the first complete backward angle asymmetry measurements since the SAMPLE experiment, at the four-momentum transfers

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confidence: 99%

Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Androić¹,

Armstrong²,

Arvieux³

et al. 2010

Phys. Rev. Lett.

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137

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“…Latest polarized electron source can provide up to 90% polarization. Beam polarization is usually measured after acceleration using a Møller polarimeter [28] each few days. To avoid any slow systematic drifts (like temperature sensitivity of the experimental setup, beam depolarization, etc...), helicity of the electron beam is reversed, at a frequency of few Hz using a randomly chosen pattern of helicity states.…”

Section: Experimental Overviewmentioning

confidence: 99%

Recent results from theG⁰experiment

Réal

Androić

Armstrong

et al. 2010

EPJ Web of Conferences

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Abstract. We have measured parity violating asymmetries in elastic electron-proton and quasi-elastic electrondeuteron scattering at backward electron angle. These measurements have been done at two momentum transfers : Q 2 = 0.22 and 0.63 (GeV/c) 2 . Together with our previous forward angle measurement [1], we can extract strange quark contributions to the electromagnetic form factors of the nucleon, as well as nucleon axial form factor coming from the neutral weak interaction. The results indicate a strange quark magnetic contribution close to zero at these Q 2 , and a possible non zero strange quark electric contribution for the high Q 2 . The first Q 2 behavior measurement of the nucleon axial form factor in elastic electron scattering shows a good agreement with radiative corrections calculated at Q 2 = 0 and with a dipole form using the axial mass determined in neutrino scattering.

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“…In extracted beams, Møller polarimetry typically has to use beam currents much lower than the PV experiments need. Extrapolation of the results to the experimental conditions introduces a systematic error, which is sometimes hard to evaluate, in particular in case of JLab where the beam in a certain hall may contain a leakage from a differently polarized beam for another hall [3]. Møller polarimetry with these targets is invasive and typically requires a different beam tuning.…”

Section: Møller Scatteringmentioning

confidence: 99%

“…The "beams" may have different currents and polarizations. A small leakage from a differently polarized beam may introduce a considerable systematic error [3]. Variations of the electron polarization at the source is also a possibility.…”

Section: Introductionmentioning

confidence: 99%

Precision electron polarimetry

Chudakov

2013

AIP Conference Proceedings

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Abstract.A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Møller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Møller polarimetry.

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Erratum: Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement [Phys. Rev. ST Accel. Beams7, 042802 (2004)]

Cited by 12 publications

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Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Recent results from theG⁰experiment

Precision electron polarimetry

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Erratum: Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement [Phys. Rev. ST Accel. Beams7, 042802 (2004)]

Cited by 12 publications

References 0 publications

Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Recent results from theG0experiment

Precision electron polarimetry

Contact Info

Product

Resources

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Recent results from theG⁰experiment