Proton DAQ Trigger Efficiency in the Nab Experiment

Nab is a precision neutron β-decay experiment that measures the electron–antineutrino correlation coefficient a and the Fierz interference term b by measuring proton time-of-flight (TOF) and electron energy (Eₑ) with silicon detectors and a hardware trigger. A TOF-dependent proton-trigger efficiency can bias a. We present a data-driven assessment of the per-channel noise, extracted from DAQ-recorded baseline power spectral densities (PSD), matched to a singular value decomposition (SVD)-derived proton template and evaluated with an emulated DAQ trigger. We report efficiency versus threshold, amplitude, and TOF, with uncertainty bands combining binomial counting and noise-mixing variance. The resulting channel-resolved efficiency maps are applied to correct TOF-binned proton yields and propagated as a systematic on a.