STI Publications - View Publication Form #14091
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Publication Information
| Title | The Qweak Experiment: First Determination of the Weak Charge of the Proton | ||||
| Abstract | 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 result reported here is extracted from the commissioning part of the experiment, constituting about 4% of the full data set. The parity-violating asymmetry at a low momentum transfer $Q^2$=0.025 GeV$^2$ is $A_{ep}$ = -279 $\pm$ 35 (stat) $\pm$ 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in $\vec{e}$p scattering. This result allowed the first determination of the weak charge of the proton $Q_W^p$ from a global fit of parity-violating elastic scattering (PVES) results from nuclear targets, where earlier data at higher $Q^2$ constrain uncertainties of hadronic structure. The value extracted from the global fit is $Q_W^p$ (PVES) = 0.064 $\pm$ 0.012, in agreement with the standard model prediction $Q_W^p$ (SM) = 0.0710 $\pm$ | ||||
| Author(s) | Emmanouil Kargiantoulakis | ||||
| Publication Date | August 2015 | ||||
| Document Type | Meeting, Proceedings | ||||
| Primary Institution | Thomas Jefferson National Accelerator Facility, Newport News | ||||
| Affiliation | Exp Nuclear Physics / Experimental Halls / Hall C | ||||
| Funding Source | Nuclear Physics (NP) | ||||
| Proprietary? | No | ||||
| This publication conveys | Technical Science Results | ||||
| Document Numbers |
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| Associated with an experiment | Yes | ||||
| Experiment Number(s) |
E08-016
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| Associated with EIC | No | ||||
| Supported by Jefferson Lab LDRD Funding | No |
Meeting / Conference
| Meeting Name | CIPANP 2015 |
| Meeting Date | 5/21/2015 |
| Document Subtype | Paper (proceedings only) |
Proceedings
| Title | Proceedings of CIPANP 2015 |
| Editor(s) | Bonnie Fleming and Wick Haxton |
| Publisher | SLAC eConf |
| Refereed | No |
| Page Number | 13 |
| Year | 2015 |
Attachments/Datasets/DOI Link
| Document(s) |
1509.08829v2.pdf
(STI Document)
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| Dataset(s) | (none) |
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