Bates Parity Experiment on Elastic Electron Carbon Scattering

We have measured the parity-violating electroweak asymmetry in the elastic scattering of longitudinally polarized electrons from 12C nuclei. Our result for the experimental asymmetry is Aexp = 0.60 ± 0.14 ± 0.02 ppm, where the first error is statistical and the second is systematic. With a beam polarization of 0.37 ± 0.02, we deduce a value for the isoscalar vector hadronic coupling constant \(\widetilde{\gamma }\) of 0.136 ± 0.032 ± 0.009, which is in agreement with the standard model prediction of \(\widetilde{\gamma }\) = 0.155.