# Search for neutrinoless quadruple-$\beta$ decay of $^{150}$Nd with the NEMO-3 detector

## TL;DR

This paper reports the first experimental search for neutrinoless quadruple-beta decay in $^{150}$Nd, setting new lower limits on its half-life and thus constraining lepton number violation models.

## Contribution

First experimental search for neutrinoless quadruple-beta decay of $^{150}$Nd using the NEMO-3 detector, establishing new half-life lower bounds.

## Key findings

- No evidence of decay observed.
- Lower limits on half-life range from 1.1 to 3.2 x 10^{21} years.
- Constraints on lepton number violation models.

## Abstract

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-$\beta$ decay of $^{150}$Nd using a total exposure of $0.19$ kg$\cdot$y recorded with the NEMO-3 detector at the Modane Underground Laboratory (LSM). We find no evidence of this decay and set lower limits on the half-life in the range $T_{1/2}>(1.1-3.2)\times10^{21}$ y at the $90\%$ CL, depending on the model used for the kinematic distributions of the emitted electrons.