The elastic electron-proton ($e-p$) scattering and the spectroscopy of hydrogen atoms are the two traditional methods to determine the proton charge radius ($r_{p}$). In 2010, a new method using the muonic hydrogen ($\\mu$H)\\footnote{A muonic hydrogen has its orbiting electron replaced by a muon.} spectroscopy reported a $r_{p}$ result that was nearly ten times more precise but significantly smaller than the values from the compilation of all previous $r_{p}$ measurements, creating the ``proton charge radius puzzle\".
In order to investigate the puzzle,
the PRad experiment (E12-11-106\\footnote{Spokespersons: A. Gasparian (contact), H. Gao, M. Khandaker, D. Dutta}) was first proposed in 2011 and performed in 2016 in Hall B at the Thomas Jefferson National Accelerator Facility, with both 1.1 and 2.2 GeV electron beams. The experiment measured the $e-p$ elastic scattering cross sections in an unprecedented low values of momentum transfer squared region ($Q^2 = 2.1\\times10^{-4} - 0.06~\\rm{(GeV/c)}^2$), with a sub-percent precision.
The PRad experiment utilized a calorimetric method that was magnetic-spectrometer-free. Its detector setup included a large acceptance and high resolution calorimeter (HyCal), and two large-area, high-spatial-resolution Gas Electron Multiplier (GEM) detectors. To have a better control over the systematic uncertainties, the absolute $e-p$ elastic scattering cross section was normalized to that of the well-known M$\\o$ller scattering process, which was measured simultaneously during the experiment. For each beam energy, all data with different $Q^{2}$ were collected simultaneously with the same detector setup, therefore sharing a common normalization parameter. The windowless H$_2$ gas-flow target utilized in the experiment largely removed a typical background source, the target cell windows. The proton charge radius was determined as $r_{p} = 0.831 \\pm 0.007_{\\rm{stat.}} \\pm 0.012_{\\rm{syst.}}$~fm, which is smaller than the average $r_{p}$ from previous $e-p$ elastic scattering experiments, but in agreement with the $\\mu$H spectroscopic results within the experimental uncertainties.
","abstract_html":"<p>The elastic electron-proton ($e-p$) scattering and the spectroscopy of hydrogen atoms are the two traditional methods to determine the proton charge radius (rp). In 2010, a new method using the muonic hydrogen (μH)\\footnote{A muonic hydrogen has its orbiting electron replaced by a muon.} spectroscopy reported a rp result that was nearly ten times more precise but significantly smaller than the values from the compilation of all previous rp measurements, creating the ``proton charge radius puzzle".</p><p>In order to investigate the puzzle, </p><p>the PRad experiment (E12-11-106\\footnote{Spokespersons: A. Gasparian (contact), H. Gao, M. Khandaker, D. Dutta}) was first proposed in 2011 and performed in 2016 in Hall B at the Thomas Jefferson National Accelerator Facility, with both 1.1 and 2.2 GeV electron beams. The experiment measured the $e-p$ elastic scattering cross sections in an unprecedented low values of momentum transfer squared region (Q2 = 2.1\\times10-4 - 0.06~\\rm{(GeV/c)}2), with a sub-percent precision.</p><p>The PRad experiment utilized a calorimetric method that was magnetic-spectrometer-free. Its detector setup included a large acceptance and high resolution calorimeter (HyCal), and two large-area, high-spatial-resolution Gas Electron Multiplier (GEM) detectors. To have a better control over the systematic uncertainties, the absolute $e-p$ elastic scattering cross section was normalized to that of the well-known M$\\o$ller scattering process, which was measured simultaneously during the experiment. For each beam energy, all data with different Q2 were collected simultaneously with the same detector setup, therefore sharing a common normalization parameter. The windowless H2 gas-flow target utilized in the experiment largely removed a typical background source, the target cell windows. The proton charge radius was determined as rp = 0.831 \\pm 0.007\\rm{stat.} \\pm 0.012\\rm{syst.}~fm, which is smaller than the average rp from previous $e-p$ elastic scattering experiments, but in agreement with the μH spectroscopic results within the experimental uncertainties.</p>","abstract_has_math":true,"creators":["Xiong, Weizhi"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Gao, Haiyan"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020","date_published":"2020","updated_at":"2026-07-24T02:07:10Z","subjects":["Particle physics","Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10161/20844","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Gao, Haiyan"]},{"key":"dc:creator","label":"Author","values":["Xiong, Weizhi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2020-06-09T17:58:12Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2020-06-09T17:58:12Z"]},{"key":"dc:date.issued","label":"Date","values":["2020"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Particle physics","Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10161/20844"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The elastic electron-proton ($e-p$) scattering and the spectroscopy of hydrogen atoms are the two traditional methods to determine the proton charge radius ($r_{p}$). In 2010, a new method using the muonic hydrogen ($\\mu$H)\\footnote{A muonic hydrogen has its orbiting electron replaced by a muon.} spectroscopy reported a $r_{p}$ result that was nearly ten times more precise but significantly smaller than the values from the compilation of all previous $r_{p}$ measurements, creating the ``proton charge radius puzzle\".
In order to investigate the puzzle,
the PRad experiment (E12-11-106\\footnote{Spokespersons: A. Gasparian (contact), H. Gao, M. Khandaker, D. Dutta}) was first proposed in 2011 and performed in 2016 in Hall B at the Thomas Jefferson National Accelerator Facility, with both 1.1 and 2.2 GeV electron beams. The experiment measured the $e-p$ elastic scattering cross sections in an unprecedented low values of momentum transfer squared region ($Q^2 = 2.1\\times10^{-4} - 0.06~\\rm{(GeV/c)}^2$), with a sub-percent precision.
The PRad experiment utilized a calorimetric method that was magnetic-spectrometer-free. Its detector setup included a large acceptance and high resolution calorimeter (HyCal), and two large-area, high-spatial-resolution Gas Electron Multiplier (GEM) detectors. To have a better control over the systematic uncertainties, the absolute $e-p$ elastic scattering cross section was normalized to that of the well-known M$\\o$ller scattering process, which was measured simultaneously during the experiment. For each beam energy, all data with different $Q^{2}$ were collected simultaneously with the same detector setup, therefore sharing a common normalization parameter. The windowless H$_2$ gas-flow target utilized in the experiment largely removed a typical background source, the target cell windows. The proton charge radius was determined as $r_{p} = 0.831 \\pm 0.007_{\\rm{stat.}} \\pm 0.012_{\\rm{syst.}}$~fm, which is smaller than the average $r_{p}$ from previous $e-p$ elastic scattering experiments, but in agreement with the $\\mu$H spectroscopic results within the experimental uncertainties.
"]},{"key":"dc:title","label":"Title","values":["A High Precision Measurement of the Proton Charge Radius at JLab"]}]}],"canonical_facts":{"dc:contributor.advisor":["Gao, Haiyan"],"dc:creator":["Xiong, Weizhi"],"dc:date.accessioned":["2020-06-09T17:58:12Z"],"dc:date.available":["2020-06-09T17:58:12Z"],"dc:date.issued":["2020"],"dc:description.abstract":["The elastic electron-proton ($e-p$) scattering and the spectroscopy of hydrogen atoms are the two traditional methods to determine the proton charge radius ($r_{p}$). In 2010, a new method using the muonic hydrogen ($\\mu$H)\\footnote{A muonic hydrogen has its orbiting electron replaced by a muon.} spectroscopy reported a $r_{p}$ result that was nearly ten times more precise but significantly smaller than the values from the compilation of all previous $r_{p}$ measurements, creating the ``proton charge radius puzzle\".
In order to investigate the puzzle,
the PRad experiment (E12-11-106\\footnote{Spokespersons: A. Gasparian (contact), H. Gao, M. Khandaker, D. Dutta}) was first proposed in 2011 and performed in 2016 in Hall B at the Thomas Jefferson National Accelerator Facility, with both 1.1 and 2.2 GeV electron beams. The experiment measured the $e-p$ elastic scattering cross sections in an unprecedented low values of momentum transfer squared region ($Q^2 = 2.1\\times10^{-4} - 0.06~\\rm{(GeV/c)}^2$), with a sub-percent precision.
The PRad experiment utilized a calorimetric method that was magnetic-spectrometer-free. Its detector setup included a large acceptance and high resolution calorimeter (HyCal), and two large-area, high-spatial-resolution Gas Electron Multiplier (GEM) detectors. To have a better control over the systematic uncertainties, the absolute $e-p$ elastic scattering cross section was normalized to that of the well-known M$\\o$ller scattering process, which was measured simultaneously during the experiment. For each beam energy, all data with different $Q^{2}$ were collected simultaneously with the same detector setup, therefore sharing a common normalization parameter. The windowless H$_2$ gas-flow target utilized in the experiment largely removed a typical background source, the target cell windows. The proton charge radius was determined as $r_{p} = 0.831 \\pm 0.007_{\\rm{stat.}} \\pm 0.012_{\\rm{syst.}}$~fm, which is smaller than the average $r_{p}$ from previous $e-p$ elastic scattering experiments, but in agreement with the $\\mu$H spectroscopic results within the experimental uncertainties.
"],"dc:identifier.uri":["https://hdl.handle.net/10161/20844"],"dc:subject":["Particle physics","Physics"],"dc:title":["A High Precision Measurement of the Proton Charge Radius at JLab"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T02:07:10Z"}