Signal identification with Kalman Filter towards background-free neutrinoless double beta decay searches in gaseous detectors

摘要

A bstract Particle tracks and differential energy loss measured in high pressure gaseous detectors can be exploited for event identification in neutrinoless double beta decay (0 νββ ) searches. We develop a new method based on Kalman Filter in a Bayesian formalism (KFB) to reconstruct meandering tracks of MeV-scale electrons. With simulation data, we compare the signal and background discrimination power of the KFB method assuming different detector granularities and energy resolutions. Typical background from~(232)Th and~(238)U decay chains can be suppressed by another order of magnitude than that in published literatures, approaching the background-free regime. For the proposed PandaX-III experiment, the 0 νββ search half-life sensitivity at the 90% confidence level would reach 2 . 7 × 10~(26)yr with 5-year live time, a factor of 2.7 improvement over the initial design target.