The Q-Weak Experiment: Measurement of the Weak Charge of the Proton

29 Apr 2015, 11:10


WG3 Electroweak Physics and Beyond the Standard Model WG3:Electroweak Physics and Beyond the Standard Model


Dave Gaskell (Jefferson Lab)


The weak charge of the proton, $Q^p_{W}$, has been measured precisely for the first time at Jefferson Lab. The running of the weak mixing angle ($\sin^2\theta_W/2$), and thus $Q^p_{W}$, from the $Z$-pole to the low momentum transfers of this measurement is potentially sensitive through radiative corrections to new physics beyond the Standard Model. The Q-Weak experiment ran in Hall C from 2010-2012 and measured the parity-violating asymmetry in elastic electron-proton scattering at $Q^2$=0.025 (GeV/$c$)$^2$. This talk will present the initial results from this experiment from about 4% of the total data sample collected. $Q^p_W$ was extracted using this data point in combination with higher $Q^2$ parity-violating electron-scattering data and state-of-the-art theoretical calculations, used to constrain hadronic effects. The analysis status of the full data set, as well as several ancillary measurements will also be discussed.

Primary author

Dave Gaskell (Jefferson Lab)

Presentation Materials