Electron neutrino charged current interaction studies on ¹²⁷I with the COHERENT 185 kg NaI detector

An inclusive measurement of the cross section of the neutrino charged-current interactions on ¹²⁷I can probe the quenching of g_A, the axial-vector coupling constant, which affects the rate of neutrinoless double beta decays. At the Los Alamos Meson Production Facility (LAMPF), an exclusive measurement of the flux-averaged cross section was made but with a large statistical error. To make a first measurement of the inclusive cross section with low statistical uncertainty, a 185 kg NaI[Tl] prototype was deployed by the COHERENT collaboration at the Spallation Neutron Source. To reduce the major background, cosmic muons, a convolutional neural network (CNN) classifier and a random forest classifier were developed (the best 2-class model, tested with simulations, achieved a 94% classification accuracy assuming nano-second timing resolutions). To address the non-linearity of NaI[Tl] crystals at high energies, calibrations using Michel electrons from stopped muon decays are underway. Data analysis is ongoing and latest results will be presented.