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New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors

HAPPEX collaboration·K. A. Aniol
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Abstract

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) +- 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the strange form factor (G_E^s + 0.392 G_M^s) = 0.025 +- 0.020 +- 0.014, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a `strained' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.

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HAPPEX collaboration, K. A. Aniol. 2001-04-12. New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors. https://doi.org/10.1016/s0370-2693(01)00446-4

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