Methodology and Progress of SBS-GMn Physics Analysis

Nucleon elastic form factors help us understand the nucleon structure by probing its four-current distributions. But very little is known of the neutron's magnetic form factor, $G^{n}_{M}$, for $Q^2 > 4$ $(GeV/c)^2$. To shed some light on this area, the $SBS$-$G_M^n$ experiment (E12-09-019) ran in Jefferson Lab's experimental Hall A from fall 2021 to February 2022 and took data for several high precision measurements of $G_M^n$ in the range 3 ≤ $Q^2$ ≤ 13.6 $(GeV/c)^2$ using ``ratio" method. Systematic errors are greatly reduced by the use of ``ratio" method in which $G_M^n$ is extracted from the ratio of neutron-coincident to proton-coincident quasi-elastic electron scattering from deuteron. Despite various challenges the data taking was successful and significant progress on detector calibration and physics analysis has been made so far. In this talk, I will discuss our methodology and present our progress of physics analysis including preliminary data/MC comparisons that were achieved by using our simulation, digitization, and reconstruction machinery, preliminary nucleon detection efficiency analysis, and preliminary raw elastic yield extractions. I will also show realistic projections of the final uncertainties on $G_M^n$, emphasizing the high-$Q^2$ data points.