# Demonstration of the event identification capabilities of the NEXT-White detector

## TL;DR

This paper demonstrates the ability of the NEXT-White detector to identify double-electron events, achieving significant background rejection and efficiency, which enhances the sensitivity of neutrinoless double-beta decay searches.

## Contribution

First measurement of event signature-based cut efficiency for double-electron tracks using NEXT-White detector data, with results aligning with Monte Carlo simulations.

## Key findings

- Signal efficiency of 71.6% at 1.6 MeV
- Background acceptance of 20.6% at 1.6 MeV
- Improved background rejection extrapolated to decay energies

## Abstract

In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a \TO\ calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of $71.6 \pm 1.5_{\textrm{ stat}} \pm 0.3_{\textrm{ sys}} \%$ for a background acceptance of $20.6 \pm 0.4_{\textrm{ stat}} \pm 0.3_{\textrm{ sys}} \%$ is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies.