UCNB: Precise Measurement of the Neutrino Asymmetry from Polarized $\beta$-decay

The UCNB experiment aims to measure the neutrino asymmetry, $B$, from free neutron decay using the ultracold neutron source at the Los Alamos Neutron Science Center. A precise measurement of $B$ yields insight into physics such as right-handed currents, and provides a sensitive channel to probe for exotic scalar and tensor couplings. By instrumenting the existing UCNA spectrometer with thick, highly-segmented silicon detectors, coincident electron and proton pairs from UCN decays have been directly measured, allowing for a determination of $B$. Presented here will be an analysis of the 2015-2016 data and a study of the potential sources of systematic error for a measurement of the $B$ coefficient. The goal of the UCNB experiment is to determine the neutrino asymmetry to a precision of $\delta B/B \approx 10^{-3}$.