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The weak charge of the proton $Q_{\textrm{w}}$ is one of the most fundamental quantities in physics. It can be determined by measuring the parity asymmetry $A_{\textrm{PV}}$ in elastic $ep$ scattering, where the $\gamma Z$-exchange…

High Energy Physics - Phenomenology · Physics 2026-04-24 Qian-Qian Guo , Hai-Qing Zhou

In this study, we calculate the $\gamma Z$-exchange contribution to elastic $ep$ scattering at large momentum transfer within perturbative QCD. We present analytical expressions for the $\gamma Z$-exchange contributions to the amplitudes.…

High Energy Physics - Phenomenology · Physics 2026-04-24 Qian-Qian Guo , Hui-Yun Cao , Hai-Qing Zhou

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These asymmetries, arising from interference of the electromagnetic and neutral weak…

Nuclear Experiment · Physics 2012-08-27 The G0 Collaboration

We calculate the parity-nonconserving longitudinal asymmetry in the elastic $\vec{p} p$ scattering at the energies where experimental data are available. In addition to the standard one-meson exchange weak potential, the variation of the…

Nuclear Theory · Physics 2016-09-08 C. H. Hyun , C. -P. Liu , B. Desplanques

We review the state-of-the-art and address open questions relative to the theory uncertainty of the $\gamma-Z$ box contribution to the $A_{PV}$ measurement within the QWEAK experiment at Jefferson Lab. This white paper summarizes the…

High Energy Physics - Phenomenology · Physics 2013-11-20 Mikhail Gorchtein , Jens Erler , Tobias Hurth , Hubert Spiesberger , Krishna Kumar , Michael J. Ramsey-Musolf , Harvey B. Meyer

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…

Nuclear Experiment · Physics 2015-06-18 Nuruzzaman

The fields of particle and nuclear physics have undertaken extensive programs to search for evidence of physics beyond that explained by current theories. The observation of the Higgs boson at the Large Hadron Collider completed the set of…

Radiative corrections to parity violating deep inelastic electron scattering are reviewed including a discussion of the renormalization group evolution of the weak mixing angle. Recently obtained results on hypothetical Z' bosons - for…

High Energy Physics - Phenomenology · Physics 2009-09-30 Jens Erler

We study parity violation in quasielastic (QE) electron-nucleus scattering using the relativistic impulse approximation. Different fully relativistic approaches have been considered to estimate the effects associated with the final-state…

Nuclear Theory · Physics 2015-04-15 R. González-Jiménez , J. A. Caballero , T. W. Donnelly

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…

Nuclear Experiment · Physics 2016-01-28 Donald Jones

The role of relativistic corrections associated with lower Dirac components of the deuteron wavefunction, is examined for parity-violating (PV) electron scattering. The relation between these corrections and negative energy components of…

Nuclear Theory · Physics 2009-10-30 G. I. Poulis

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2= 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form…

Nuclear Experiment · Physics 2014-11-18 SAMPLE collaboration , T. M. Ito

We calculate polarization phenomena for virtual Compton scattering on protons, at relatively large momentum transfer 1 GeV$^2$ $\le -q^2\le$ 5 GeV$^2$ on the basis of a model for $\gamma^*+ p\to \gamma+p$ with two main contributions:…

Nuclear Theory · Physics 2007-05-23 M. P. Rekalo , E. Tomasi-Gustafsson

The weak charge $Q_W$ measured in atomic parity violation experiments can receive compensating contributions from more than one new physics source. We show explicitly that the $\Delta Q_W$ contribution from the exchange of an extra Z-boson…

High Energy Physics - Phenomenology · Physics 2009-09-15 V. Barger , K. Cheung , D. P. Roy , D. Zeppenfeld

We report on a calculation of one-loop weak corrections to polarized quark-gluon scattering and the corresponding crossed channels. Such contributions are suppressed formally by one power of alpha_s relative to W- or Z-mediated quark-quark…

High Energy Physics - Phenomenology · Physics 2009-11-07 John Ellis , Stefano Moretti , Douglas Ross

The effect of vacuum polarization on the parity violating asymmetry in the elastic electron-nucleus scattering is considered. Calculations are performed in the high-energy approximation with an exact account for the electric field of the…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. I. Milstein , O. P. Sushkov

The GEp-III and GEp-2$\gamma$ experiments were carried out in Jefferson Lab's (JLab's) Hall C from 2007-2008, to extend the knowledge of $G_E^p/G_M^p$ to the highest practically achievable $Q^2$ and to search for effects beyond the Born…

We present an analysis of elastic and quasielastic parity-violating (PV) electron scattering processes. These reactions can help to constrain the weak neutral current form factors of the nucleon that play an essential role in the…

Nuclear Theory · Physics 2020-01-27 R. González-Jiménez , J. A. Caballero , T. W. Donnelly

We present an evaluation of box diagram for the elastic $ep$ scattering with proton in the intermediate state. Using analytic properties of the proton form factors we express the amplitude via twofold integral, which involves the form…

Nuclear Theory · Physics 2008-11-26 Dmitry Borisyuk , Alexander Kobushkin

Higher-order QED effects play an important role in precision measurements of nucleon elastic form factors in electron scattering. Here we introduce a two-photon exchange QED correction to the parity-violating polarization asymmetry of…

High Energy Physics - Phenomenology · Physics 2008-11-26 Andrei V. Afanasev , Carl E. Carlson