Speaker
Description
Two photon exchange is one possible explanation for the disparity in the proton form factor ratio when comparing results from Rosenbluth scattering and polarization transfer experiments. To measure the effect of two photon exchange alone we intend to compare the different scattering asymmetries for electrons and positrons scattering off a polarized proton target. The asymmetry difference in these two measurements results from the sign of their charge alone, which is related solely to two photon exchange. Using a Monte Carlo simulation to account for the CLAS detector acceptance, beam shift due to the target holding field, and factoring in uncertainties from target dilution and detector resolution we are able to estimate the required beamtime to measure two photon exchange with sufficient certainty.
