# Discovery probability of next-generation neutrinoless double-$\beta$ decay experiments

## TL;DR

This paper assesses the likelihood of detecting neutrinoless double-beta decay in future experiments, showing higher discovery probabilities than previously thought, especially for inverted neutrino mass ordering.

## Contribution

It introduces a Bayesian global fit approach to estimate discovery probabilities, incorporating experimental sensitivities and neutrino mass ordering effects.

## Key findings

- Higher discovery probabilities than earlier estimates.
- Inverted mass ordering significantly increases detection chances.
- Potential for ~50% discovery probability in the most promising experiments.

## Abstract

The Bayesian discovery probability of future experiments searching for neutrinoless double-$\beta$ decay is evaluated under the popular assumption that neutrinos are their own antiparticles. A Bayesian global fit is performed to construct a probability distribution for the effective Majorana mass, the observable of interest for these experiments. This probability distribution is then combined with the sensitivity of each experiment derived from a heuristic counting analysis. The discovery probability is found to be higher than previously considered, but strongly depends on whether the neutrino mass ordering is normal or inverted. For the inverted ordering, next-generation experiments are likely to observe a signal already during their first operational stages. Even for the normal ordering, in the absence of neutrino mass mechanisms that drive the lightest state or the effective Majorana mass to zero, the probability of discovering neutrinoless double-$\beta$ decay can reach $\sim$50% or more in the most promising experiments.