Determination of the Kinematics of the Qweak Experiment and Investigation of an Atomic Hydrogen Moller Polarimeter
- College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
The Qweak experiment has tested the Standard Model through making a precise measurement of the weak charge of the proton ($$Q^p_W$$). This was done through measuring the parity-violating asymmetry for polarized electrons scattering off of unpolarized protons. The parity-violating asymmetry measured is directly proportional to the four-momentum transfer ($Q^2$) from the electron to the proton. The extraction of $$Q^p_W$$ from the measured asymmetry requires a precise $Q^2$ determination. The Qweak experiment had a $Q^2$ = 24.8 ± 0.1 m(GeV2) which achieved the goal of an uncertainty of <= 0.5%. From the measured asymmetry and $Q^2$, $$Q^p_W$$ was determined to be 0.0719 ± 0.0045, which is in good agreement with the Standard Model prediction. This puts a 7.5 TeV lower limit on possible "new physics". This dissertation describes the analysis of Q^2 for the Qweak experiment. Future parity-violating electron scattering experiments similar to the Qweak experiment will measure asymmetries to high precision in order to test the Standard Model. These measurements will require the beam polarization to be measured to sub-0.5% precision. Presently the electron beam polarization is measured through Moller scattering off of a ferromagnetic foil or through using Compton scattering, both of which can have issues reaching this precision. A novel Atomic Hydrogen Moller Polarimeter has been proposed as a non-invasive way to measure the polarization of an electron beam via Moller scattering off of polarized monatomic hydrogen gas. This dissertation describes the development and initial analysis of a Monte Carlo simulation of an Atomic Hydrogen Moller Polarimeter.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177; NSF-PHY-1405857; NSF-PHY-1206053
- OSTI ID:
- 1417891
- Report Number(s):
- JLAB-PHY-18-2626; DOE/OR/23177-4327
- Country of Publication:
- United States
- Language:
- English
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