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

Abstract

Particle tracks and differential energy loss measured in high pressure gaseous detectors can be exploited for event identification in neutrinoless double beta decay (0νββ) 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 232Th and 238U 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 0νββ search half-life sensitivity at the 90% confidence level would reach 2.7× 1026 yr with 5-year live time, a factor of 2.7 improvement over the initial design target.

School of Mechanical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China

“…Nowadays, TPCs are playing a critical role in rare event search experiments, such as Neutrinoless Double Beta Decay (NLDBD) searches (e.g., NEXT [2], EXO-200 [3]), and dark matter direct detections (e.g., XENON1T [4], TREX-DM [5], and PandaX-4T [6]). A gaseous TPC can record both energy depositions and trajectories of charged particles traveling within, providing information to discriminate the signal from the background [7][8][9].…”

Status and prospects of the PandaX-III experiment

“…The expected energy resolution is 3% FWHM (Full Width at Half Maximum) at the Q-value (2458 keV). The track of MeV-scale electrons in 10 bar xenon is long enough (about 10.0 cm), therefore the topological information is powerful for signal-background discrimination [7][8][9][10][11]. The construction of the detector was completed.…”

“…These rare event search experiments demand a very sensitive detector with low radioactivity, high energy resolution, and good imaging capabilities. A gaseous TPC can record the energy depositions and reconstruct the tracks of events, providing powerful discrimination of the signal from the background for NLDBD searches [7][8][9][10][11].…”

Calibration of a Micromegas-based gaseous time projection chamber using cosmic ray muons

“…Nowadays, TPCs are playing a critical role in rare event search experiments, such as Neutrinoless Double Beta Decay (NLDBD) searches (e.g., NEXT [2], EXO-200 [3]), and dark matter direct detections (e.g., XENON1T [4], TREX-DM [5], and PandaX-4T [6]). A gaseous TPC can record both energy depositions and trajectories of charged particles traveling within, providing information to discriminate the signal from the background [7,8].…”