Measurement of the Proton Electric Form Factor ratio G^p_E at Large Momentum Transfer

Nucleon elastic form factors give important insights into the nucleon structure, and electron scattering is one of the simplest probes of the internal nucleon structure. The Super Bigbite Spectrometer (SBS) program at JLab will measure the elastic nucleon form factors at large momentum transfer, including a measurement of the proton electromagnetic form factor G^p_E at momentum transfer up to 12 GeV². Little is known about the proton form factor at high momentum transfer, no data has been measured for G^p_E at Q² > 8.5 GeV². The approved experiment, E12-07-109, will use the recoil polarization technique and aims to make precision measurements at Q² = 5.5, 8, and 12 GeV² and will start in early 2025. Work is underway to construct a new electromagnetic calorimeter capable of withstanding the high radiation load necessary for a precision measurement at large Q². The 1656 lead glass crystals will be placed in a custom heater, capable of annealing the crystals at 220 deg C. An overview of the SBS-G^p_E experimental method and the development of multiple novel detectors, including the progress of the electromagnetic calorimeter and the completion of a small-scale test will be discussed