Related papers: The Qweak Experiment -- A search for new physics a…
We propose a new precision measurement of parity-violating electron scattering on the proton at very low Q^2 and forward angles to challenge predictions of the Standard Model and search for new physics. A unique opportunity exists to carry…
The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low $Q^2$ of a longitudinally polarized electron beam on a proton target. The experiment will measure the…
From a distance, the proton's weak charge is seen through the distorting effects of clouds of virtual particles. The effective weak charge can be calculated by starting with the measured weak coupling at the Z-pole and "running" the…
A subset of results from the recently completed Jefferson Lab Qweak experiment are reported. This experiment, sensitive to physics beyond the Standard Model, exploits the small parity-violating asymmetry in elastic ep scattering to provide…
The Qweak experiment which ran at Jefferson Lab in Newport News, VA, measured the weak charge of the proton $Q_W^p$ via elastic electron-proton scattering. Longitudinally polarized electrons were scattered from an unpolarized liquid…
The Qweak experiment at Jefferson Laboratory measures the parity violating asymmetry of polarized electrons scattering from a proton target at very low momentum transfer. In the Standard Model, this asymmetry reveals the proton's coupling…
The Qweak experiment has measured the parity-violating asymmetry in polarized e-p elastic scattering at Q^2 = 0.025(GeV/c)^2, employing 145 microamps of 89% longitudinally polarized electrons on a 34.4cm long liquid hydrogen target at…
The Q-weak experiment at Hall C of Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton, Qweak(p), through a precision measurement of the parity-violating asymmetry in elastic…
The MOLLER experiment will measure the weak charge of the electron, $Q^e_W = 1 - 4\sin^2\theta_W$, with a precision of 2.3% by measuring the parity-violating asymmetry in electron-electron (M\oller) scattering. This measurement will provide…
The Jefferson Lab Q_weak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from an unpolarized liquid hydrogen target at small momentum…
The $Q_{weak}$ Collaboration has completed a challenging measurement of the parity-violating asymmetry in elastic electron-proton ($\vec{e}$p) scattering at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The initial…
After almost five decades of study of parity violation in hadronic systems, the determination of the seven weak meson-nucleon couplings is still incomplete. Whereas parity violation in nuclear systems is complicated by the intricacies of…
A forthcoming experiment of low-energy elastic electron proton scattering at the new MESA facility in Mainz is planned to provide a high-precision measurement of the parity-violating polarisation asymmetry. This experiment is expected to…
This article describes the future P2 parity-violating electron scattering facility at the upcoming MESA accelerator in Mainz. The physics program of the facility comprises indirect, high precision search for physics beyond the Standard…
The impact of atomic parity violation experiments on determination of the weak mixing parameter $\sin^2 \theta$ and the Peskin-Takeuchi parameters $S$ and $T$ is reassessed in the light of recent electroweak measurements at LEP, SLAC, and…
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 =…
We address the physics implications of a precision determination of the weak charge of the proton, QWP, from a parity violating elastic electron proton scattering experiment to be performed at the Jefferson Laboratory. We present the…
We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moller) scattering: A_PV = -131 +/- 14 (stat.) +/- 10 (syst.) parts per billion, leading to the determination of the weak mixing angle…
The Qweak experiment aims to measure the weak charge of the proton to 4% via the parity-violating asymmetry ($\sim$-200 ppb) in elastic e+p scattering. The scattering rate is largely influenced by five beam parameters: horizontal position…
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level…