A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result

A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result

Bibliographic Details
Main Author: Beminiwattha, Rakitha S.
Language:English
Published: Ohio University / OhioLINK 2013
Subjects:
Nuclear Physics
Particle Physics
dissertation
weak charge
proton
effective coupling
parity violating
asymmetry
data acquisition
triggering
data analysis
software
experiment
qweak
Standard Model
New Physics
TeV
electron
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368023450
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-ohiou13680234502021-08-03T05:23:24Z A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result Beminiwattha, Rakitha S. Nuclear Physics Particle Physics dissertation weak charge proton effective coupling parity violating asymmetry data acquisition triggering data analysis software experiment qweak Standard Model New Physics TeV electron After a decade of preparations, the Qweak experiment at Jefferson Lab is making the first direct measurement of the weak charge of the proton, Q^p_W. This quantity is suppressed in the Standard Model making a good candidate for search for new physics beyond the SM at the TeV scale. Operationally, we measure a small (about -0.200 ppm) parity-violating asymmetry in elastic electron-proton scattering in integrating mode while flipping the helicity of the electrons 1000 times per second. Commissioning took place Fall 2010, and we finished taking data in early summer 2012. This dissertation is based on the data taken on an initial two weeks period (Wien0). It will provide an overview of the Qweak apparatus, description of the data acquisition and analysis software systems, and final analysis and results from the Wien0 data set. The result is a 16% measurement of the parity violating electron-proton scattering asymmetry, A = -0.2788 +/- 0.0348 (stat.) +/- 0.0290 (syst.) ppm at Q^2 = 0.0250 +/- 0.0006 (GeV)^2. From this a 21% measurement of the weak charge of the proton, Q_w^p(msr)= +0.0952 +/- 0.0155 (stat.) +/- 0.0131 (syst.) +/- 0.0015 (theory) is extracted. From this a 2% measurement of the weak mixing angle, sin^2theta_W(msr)= +0.2328 +/- 0.0039 (stat.) +/- 0.0033 (syst.) +/- 0.0004 (theory) and improved constraints on isoscalar/isovector effective coupling constants of the weak neutral hadronic currents are extracted. These results deviate from the Standard Model by one standard deviation. The Wien0 results are a proof of principle of the Qweak data analysis and a highlight of the road ahead for obtaining full results. 2013-09-24 English text Ohio University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368023450 http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368023450 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Nuclear Physics
Particle Physics
dissertation
weak charge
proton
effective coupling
parity violating
asymmetry
data acquisition
triggering
data analysis
software
experiment
qweak
Standard Model
New Physics
TeV
electron
spellingShingle Nuclear Physics
Particle Physics
dissertation
weak charge
proton
effective coupling
parity violating
asymmetry
data acquisition
triggering
data analysis
software
experiment
qweak
Standard Model
New Physics
TeV
electron
Beminiwattha, Rakitha S.
A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
author Beminiwattha, Rakitha S.
author_facet Beminiwattha, Rakitha S.
author_sort Beminiwattha, Rakitha S.
title A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
title_short A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
title_full A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
title_fullStr A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
title_full_unstemmed A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result
title_sort measurement of the weak charge of the proton through parity violating electron scattering using the qweak apparatus: a 21% result
publisher Ohio University / OhioLINK
publishDate 2013
url http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368023450
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AT beminiwattharakithas measurementoftheweakchargeoftheprotonthroughparityviolatingelectronscatteringusingtheqweakapparatusa21result
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