Final results on the 0νββ decay half-life limit of 100Mo from the CUPID-Mo experiment

Abstract

Abstract The CUPID-Mo experiment to search for 0

$$\nu \beta \beta $$

ν β β

decay in

$$^{100}$$

100

Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0

$$\nu \beta \beta $$

ν β β

decay experiment. CUPID-Mo was comprised of 20 enriched

$$\hbox {Li}_{{2}}$$

Li 2

$$^{100}$$

100

$$\hbox {MoO}_4$$

MoO 4

scintillating calorimeters, each with a mass of

$$\sim 0.2$$

∼ 0.2

kg, operated at

$$\sim 20$$

∼ 20

mK. We present here the final analysis with the full exposure of CUPID-Mo (

$$^{100}$$

100

Mo exposure of 1.47

$$\hbox {kg} \times \hbox {year}$$

kg × year

) used to search for lepton number violation via 0

$$\nu \beta \beta $$

ν β β

decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the

$$^{100}$$

100

Mo 0

$$\nu \beta \beta $$

ν β β

decay half-life of

$$T_{1/2}^{0\nu }$$

T

1 / 2

0 ν

$$> {1.8}\times 10^{24}$$

>

1.8

×

10 24

year (stat. + syst.) at 90% CI. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of

$$\left<m_{\beta \beta }\right>$$

m

β β

$$<~{(0.28{-}0.49)} $$

<

( 0.28 - 0.49 )

eV, dependent upon the nuclear matrix element utilized.