A Precision Measurement of the E+p/e−p Elastic Scattering Cross Section Ratio at the OLYMPUS Experiment
Author | : Brian Scott Henderson |
Publisher | : |
Total Pages | : 288 |
Release | : 2016 |
ISBN-10 | : OCLC:970814633 |
ISBN-13 | : |
Rating | : 4/5 (33 Downloads) |
Book excerpt: Measurements of the ratio of the proton elastic form factors ([mu]pGe/Gm) using Rosenbluth separation and those using polarization-based techniques show a strong discrepancy, which has persisted both in modern experimental results and in re-analyses of previous data. The most widely accepted hypothesis to explain this discrepancy is the treatment of the contributions from hard two-photon exchange (TPE) to elastic electron-proton scattering in the radiative corrections applied to the Rosenbluth separation measurements. Calculations of the hard TPE contribution are highly model dependent, but the effect may be measured experimentally with a precise determination of the ratio of the positron-proton and electron-proton elastic scattering cross sections. The OLYMPUS experiment collected approximately 4 fb-1 of e+p and e-p scattering data at the DORIS storage ring at DESY in 2012, with the goal of measuring the elastic [sigma]e+p/[sigma]e-p ratio over the kinematic range (0.4