Simulation, Reconstruction and Analysis Framework for the Super BigBite Spectrometer Experiments in Jefferson Lab's Hall A*

The Super BigBite Spectrometer (SBS) is a collection of apparatus designed to study exclusive and semi-inclusive two-particle coincidence reactions in high-momentum-transfer (Q²) electron-nucleus scattering at the highest luminosities Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) is capable of delivering. Its approved science program includes precision measurements of nucleon electromagnetic form factors at large Q², transvere single-spin asymmetries in Semi-Inclusive Deep Inelastic Scattering (SIDIS), tagged deep-inelastic scattering from the nucleon's pion cloud, and more. The neutron form factor program using SBS was completed in May 2024. The "flagship" SBS measurement of the proton form factor ratio G_Ep/G_Mp using polarization transfer is on the Hall A schedule starting fall 2024. The common thread in all SBS experiments is the combination of moderately large solid-angle, large momentum bite, and high-luminosity capability at forward scattering angles. Charged particle tracking in the SBS experiments is enabled by Gas Electron Multipliers (GEMs) which can operate with stable gain at very high background ionization rates. From a software standpoint, tracking in the SBS experiments is in principle straightforward, relying as it does on the assumption of straight-line tracks in field-free regions behind simple dipole magnets, but in practice is technically and computationally demanding, owing to the high raw occupancy of the detectors, the large channel counts of the SBS GEMs (and the associated data rates and volumes), and the hit reconstruction ambiguities inherent in a two-dimensional strip readout. Fast, efficient, reliable tracking with low false positives has already been achieved at raw GEM occupancies of up to 20-25%. The upcoming "flagship" experiment on G_Ep presents a qualitatively greater challenge, with expected GEM occupancies as high as 50%. In this talk, I will give an overview of the SBS simulation and analysis software, the analysis achievements from already-completed experiments, and the strategy for overcoming the reconstruction challenges of GEP, with an emphasis on tracking.