Theses and Dissertations
Issuing Body
Mississippi State University
Advisor
Dunne, James A
Committee Member
Smith, Gregory R
Committee Member
Dutta, Dipangkar
Committee Member
Moong, Gautam Rupak Lan Tai
Committee Member
Srinivasan, Radhakrishnan
Date of Degree
12-13-2014
Document Type
Dissertation - Open Access
Major
Applied Physics
Degree Name
Doctor of Philosophy (Ph.D)
College
James Worth Bagley College of Engineering
Department
Applied Physics Program
Abstract
The Qweak experiment has taken data to make a 2.5 percent measurement of parity violating elastic ep asymmetry in the four momentum transfer region of 0.0250 (GeV/c)2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin2(thetaW). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z° pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world’s highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb - May 2011, is done to extract a blinded parity violating asymmetry of size--299.7 +/- 13.4 (stat.) +/- 17.2 (syst.) +/- 68 (blinding) parts-per-billion. This resulted in a preliminary proton’s weak charge of value 0.0865 +/- 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin2(thetaW) = 0.23429 +/- 0.00211.
URI
https://hdl.handle.net/11668/18707
Recommended Citation
Subedi, Adesh, "Determination of the Weak Charge of the Proton Through Parity Violating Asymmetry Measurements in the Elastic EP Scattering" (2014). Theses and Dissertations. 1352.
https://scholarsjunction.msstate.edu/td/1352