Beyond the born approximation: A precise comparison of positron-proton and electron-proton elastic scattering in CLAS
Conference
Lachniet, J, Afanasev, A, Arrington, J et al. (2008). Beyond the born approximation: A precise comparison of positron-proton and electron-proton elastic scattering in CLAS
. 334-341. 10.1142/9789812796950_0042
Lachniet, J, Afanasev, A, Arrington, J et al. (2008). Beyond the born approximation: A precise comparison of positron-proton and electron-proton elastic scattering in CLAS
. 334-341. 10.1142/9789812796950_0042
Recent polarization transfer measurements of the ratio of elastic form factors GE/GM on the proton are not in agreement with the results of Rosenbluth-type experiments. A two photon exchange contribution to the elastic cross section is the leading theoretical candidate to explain the discrepancy. A definitive test of this theory is the direct comparison of e +p and e-p elastic scattering. A proposed measurement of this sort using a novel mixed e+e- lepton beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab is described. Preliminary results from an engineering test run showing a clear signal of elastic e+p and e-p are presented.
