Speaker
Description
Two photon exchange (TPE) and the larger class of hadronic box diagrams can be a significant radiative correction to lepton scattering and beta decay measurements. Notably, it has been hypothesized that TPE could be responsible for the proton form factor ratio discrepancy. However, these diagrams remain difficult to calculate without large uncertainty and model-dependence, and theoretical calculations of some observables sensitive to TPE are in disagreement with experimental results. Extending experimental measurements of complementary TPE observables can provide critical benchmarks for these calculations. I will summarize recent and future TPE measurements at Jefferson Lab, including those that would be made possible by the proposed addition of a positron source to Jefferson Lab’s accelerator facility.
