Final Result on the Neutrinoless Double Beta Decay of with CUPID-0
Résumé
CUPID-0, an array of cryogenic calorimeters, was the first medium-scale demonstrator of the scintillating bolometers’ technology. The first project phase (March 2017–December 2018) allowed the most stringent limit on the neutrinoless double beta decay half-life of the isotope of interest, , to be set. After a six month long detector upgrade, CUPID-0 began its second and last phase (June 2019–February 2020). In this Letter, we describe the search for neutrinoless double beta decay of with a total exposure (phase ) of of isotope. We set a limit on the half-life of to the ground state of of (90% credible interval), corresponding to an effective Majorana neutrino mass . We also set the most stringent lower limits on the neutrinoless decays of to the , , and excited states of , finding , , and (90% credible interval) respectively.