Final results on the $0\nu\beta\beta$ decay half-life limit of $^{100}$Mo from the CUPID-Mo experiment

C. Augier (1) , A.S. Barabash , F. Bellini , G. Benato (2) , M. Beretta , L. Bergé (3) , J. Billard (1) , Yu. A. Borovlev , L. Cardani , N. Casali , A. Cazes (1) , M. Chapellier (3) , D. Chiesa , I. Dafinei , F.A. Danevich , M. de Jesus (1) , P. de Marcillac (3) , T. Dixon (3) , L. Dumoulin (3) , K. Eitel , F. Ferri (2) , B.K. Fujikawa , J. Gascon (1) , L. Gironi , A. Giuliani (3) , V.D. Grigorieva , M. Gros (2) , D.L. Helis (2) , H.Z. Huang R. Huang , R. Huang , L. Imbert (3) , J. Johnston , A. Juillard (1) , H. Khalife (2) , M. Kleifges , V.V. Kobychev , Yu. G. Kolomensky , S.I. Konovalov , P. Loaiza (3) , L. Ma , E.P. Makarov , R. Mariam (3) , L. Marini , S. Marnieros (3) , X.-F. Navick (2) , C. Nones (2) , E.B. Norman , E. Olivieri (3) , J.L. Ouellet , L. Pagnanini , L. Pattavina , B. Paul (2) , M. Pavan , H. Peng , G. Pessina , S. Pirro , D.V. Poda (3) , O.G. Polischuk , S. Pozzi , E. Previtali , Th. Redon (3) , A. Rojas (4) , S. Rozov , V. Sanglard (1) , J.A. Scarpaci (3) , B. Schmidt , Y. Shen , V.N. Shlegel , V. Singh , C. Tomei , V.I. Tretyak , V.I. Umatov , L. Vagneron (1) , M. Velázquez (5) , B. Welliver , L. Winslow , M. Xue , E. Yakushev , M. Zarytskyy , A.S. Zolotarova (2)

1 IP2I Lyon - Institut de Physique des 2 Infinis de Lyon
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
3 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
4 LSM - UMR 6417 - Laboratoire Souterrain de Modane
5 SIMaP - Science et Ingénierie des Matériaux et Procédés

The CUPID-Mo experiment to search for 0$\nu\beta\beta$ decay in $^{100}$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$\nu\beta\beta$ decay experiment. CUPID-Mo was comprised of 20 enriched Li$_2$$^{100}$MoO$_4$ scintillating calorimeters, each with a mass of $\sim$ 0.2 kg, operated at $\sim$20 mK. We present here the final analysis with the full exposure of CUPID-Mo ($^{100}$Mo exposure of 1.47 kg$\times$yr) used to search for lepton number violation via 0$\nu\beta\beta$ 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 $^{100}$Mo 0$\nu\beta\beta$ decay half-life of $T^{0\nu}_{1/2} > 1.8 \times 10^{24}$ year (stat.+syst.) at 90% C.I. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of $\left < (0.28$--$0.49)$ eV, dependent upon the nuclear matrix element utilized.

Mots clés: lepton number: violation; neutrino: exchange; neutrino: Majorana: mass; neutrino: Majorana; lithium; gamma ray; angular momentum; temperature; numerical calculations: Monte Carlo; energy spectrum; X-ray; background; muon; efficiency; thermal; dimension: 2; calorimeter; scintillation counter; nucleus

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Instrumentations et Détecteurs [physics.ins-det]

C. Augier, A.S. Barabash, F. Bellini, G. Benato, M. Beretta, et al.. Final results on the $0\nu\beta\beta$ decay half-life limit of $^{100}$Mo from the CUPID-Mo experiment. European Physical Journal C: Particles and Fields, 2022, 82 (11), pp.1033. ⟨10.1140/epjc/s10052-022-10942-5⟩. ⟨hal-03597297⟩