Precision Rosenbluth Measurement of the Proton Elastic Electromagnetic Form Factors and Their Ratio at Q2=2.64, 3.20, and 4.10 GeV2
- Northwestern Univ., Evanston, IL (United States)
Due to the inconsistency in the results of the mupGEp/GMp ratio of the proton, as extracted from the Rosenbluth and recoil polarization techniques, high precision measurements of the e-p elastic scattering cross sections were made at Q2 = 2.64, 3.20, and 4.10 GeV2. Protons were detected, in contrast to previous measurements where the scattered electrons were detected, which dramatically decreased-dependent systematic uncertainties and corrections. A single spectrometer measured the scattered protons of interest while simultaneous measurements at Q2 = 0.5 GeV2 were carried out using another spectrometer which served as a luminosity monitor in order to remove any uncertainties due to beam charge and target density fluctuations. The absolute uncertainty in the measured cross sections is ~3% for both spectrometers and with relative uncertainties, random and slope, below 1% for the higher Q2 protons, and below 1% random and 6% slope for the monitor spectrometer. The extracted electric and magnetic form factors were determined to 4%-7% for GEp and 1.5% for GMp. The ratio mupGEp/GMp was determined to 4%-7% and showed mupGEp/GMp ~ 1.0. The results of this work are in agreement with the previous Rosenbluth data and inconsistent with high-Q2 recoil polarization results, implying a systematic difference between the two techniques.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 878162
- Report Number(s):
- JLAB-PHY-05-465; DOE/ER/40150-3829; TRN: US0602028
- Country of Publication:
- United States
- Language:
- English
Similar Records
Polarization transfer observables in elastic electron-proton scattering at , 5.2, 6.8, and
Proton form factor ratio, μpGEP/GMP from double spin asymmetry