SBS GEP Experiment Event Reconstruction Software

The SBS (Super Bigbite Spectrometer) program's GEP experiment has been taking data since April 2025 and will continue until August 2025. The goal is to measure the proton electric to magnetic form factor ratio ($G_E^p/G_M^p$) at $Q^2$ points of 5.732 and 11.109 GeV$^2/c^2$, using the polarization transfer technique. To collect sufficient elastic H(e,e$'$)p scattering events, an ``open geometry" configuration is used. A moderate solid-angle spectrometer, consisting of a dipole magnet, Gas Electron Multiplier (GEM) trackers, a proton polarimeter, and a hadron calorimeter, is employed to detect the recoiling protons and to measure their longitudinal and transverse polarization components. The scattered electrons are detected by a novel electron calorimeter (ECal), in coincidence with the protons, to suppress the overwhelmingly large inelastic background contributions at these high-$Q^2$ settings. The front GEM trackers, located upstream of the proton polarimeter and only a few meters from the target, are subjected to extremely high particle rates on the order of a few hundred kHz/cm$^2$, with strip occupancies approaching 50\%. Signal pile-up in both space and time on the readout strips makes 1-D and 2-D hit formation and track finding an extremely challenging task. This talk will provide an overview of the SBS GEP experiment's event reconstruction software framework, with a special focus on GEM track reconstruction.