Measurements of the Neutron Magnetic Form Factor and the Two-Photon Exchange Contribution to the Electron-Neutron Elastic Scattering Cross Section

The Super BigBite Spectrometer (SBS) program in Experimental Hall A of Jefferson Lab is a series of high-precision, large Q-squared, electromagnetic form factor experiments. GMn and nTPE were the first two experiments of the SBS program and ran from October 2021 through February 2022. Both experiments detect neutron-tagged d(e,e'n) and proton-tagged d(e,e'p) quasi-elastic electrons scattering from a deuterium target. The GMn experiment is a measurement of the magnetic form factor of the neutron, GMn, via the ratio method over a Q-squared range of 3.5 to 13.5 (GeV/c)^(2). The nTPE experiment ran in-parallel with the GMn experiment and shared an overlapping kinematic point with GMn. nTPE extends the GMn experiment to assess the differences between Rosenbluth Slop and the single-photon exchange approximation. The nTPE experiment had two kinematic settings corresponding to different electron scatting angles at a fixed Q-squared values of 4.5 (GeV/c)^(2). Comparisons of nucleon form factor ratio measurements acquired through polarization transfer and LT separation reveal discrepancies as Q-squared increases. Two-photon exchange is strongly favored as the reason for this discrepancy. GMn has been extracted at two kinematic settings corresponding to Q-squared values of 3.0 and 4.5 (GeV/c)^(2). Additionally, I will present an assessment of the differences between Rosenbluth Separation and single-photon exchange measurements.