A Measurement of the Transverse Asymmetry in Forward-Angle Electron-Carbon Scattering Using the Qweak Apparatus

The \qweak experiment at Jefferson Lab aims to achieve a 4\% measurement of the proton's weak charge by measuring the parity-violating asymmetry in elastic electron-proton scattering at low momentum-transfer squared, $Q^2$ = 0.025 (GeV/c)$^2$. The measurement utilized Jefferson Lab's high-quality beam of 89\% longitudinally polarized electrons at currents up to 180 $\mu$A. A measurement of this parity-violating asymmetry will result in a precise 0.3\% measurement of $\sin^2 \theta_W$. The Standard Model makes a firm prediction of this quantity, making the high-precision \qweak measurement sensitive to new physics at the TeV scale. The \qweak apparatus was also used to measure the transverse asymmetry of electron-carbon scattering. This quantity is an observable of the imaginary component of the two-photon exchange process. My contributions to these two projects included data taking, analysis work, quantifying background contributions, and GEANT4 simulations of the apparatus. As an additional part of my graduate training, I was part of the team that updated the CEBAF Injector MeV Mott Polarimeter.

Author

• McHugh, Martin James

Language

• en

Keyword

• Standard Model
• Parity Violation
• Carbon
• Proton
• Scattering
• Weak Interaction

Date created

• 2017

Type of Work

• Dissertation

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Physics

Degree

• Ph.D.

Advisor

• Opper, Allena K

Committee Member(s)

• Zheng, Xiaochao
• Dhuga, Kalvir
• Greisshammer, Harald W
• Feldman, Gerald

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/7h149q02c