Fitting Methods in the Nab Experiment

The Nab collaboration aims to measure the electron-neutrino correlation parameter $a$ with a relative uncertainty of about $10^{-3}$, and the Fierz interference term $b$ with absolute uncertainty of $3\times 10^{-3}$ at the Spallation Neutron Source (SNS). In Nab, $a$ is determined by combined precise determinations of the electron energy and the proton time-of-flight. In this talk, we will present a fitting method to analyze $a$ and its uncertainties, as well as specific techniques developed to increase the fitting performance based on experimental scenario.