New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors
Author | : |
Publisher | : |
Total Pages | : 4 |
Release | : 2001 |
ISBN-10 | : OCLC:871240264 |
ISBN-13 | : |
Rating | : 4/5 (64 Downloads) |
Book excerpt: 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{sub lab} = 12.3 degrees and Q2 = 0.477 (GeV/c)2. The measurement implies that the value for the strange form factor (G{sub E}{sup s} + 0.392 G{sub M}{sup s})/(G{sub M}{sup p} [mu]{sub p}) = 0.069 +- 0.056 +- 0.039, 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.