New results of 116Cd double β decay study with 116CdWO4 scintillators
Abstract
A new phase of a 116Cd double β decay experiment is in progress in the Solotvina Underground Laboratory. Four enriched 116CdWO4 scintillators with total mass of 339 g are used in a setup, whose active shield is made of 15 natural CdWO4 crystals (20.6 kg). The background rate in the energy interval 2.5-3.2 MeV is 0.03 counts/yr kg keV. The half-life for 2ν2β decay of 116Cd is measured as T1/2(2ν)=2.6+/-0.1(stat)+0.7-0.4(syst)×1019 yr. The T1/2 limits for neutrinoless 2β decay of 116Cd are set at T1/2>=0.7(2.5)×1023 yr at 90%(68%) C.L. for transition to ground state of 116Sn, while for decays to the first 2+1 and second 0+1 excited levels of 116Sn at T1/2>=1.3(4.8)×1022 yr and >=0.7(2.4)×1022 yr with 90%(68%) C.L., respectively. For 0ν2β decay with emission of one or two Majorons, the limits are T1/2(0νM1)>=3.7(5.8)×1021 yr and T1/2(0νM2)>=5.9(9.4)×1020 yr at 90%(68%) C.L. Restrictions on the value of the neutrino mass, right-handed admixtures in the weak interaction, and the neutrino-Majoron coupling constant are derived as mν<=2.6(1.4) eV, η<=3.9×10-8, λ<=3.4×10-6, and gM<=12(9.5)×10-5 at 90%(68%) C.L., respectively.
- Publication:
-
Physical Review C
- Pub Date:
- October 2000
- DOI:
- 10.1103/PhysRevC.62.045501
- arXiv:
- arXiv:nucl-ex/0003001
- Bibcode:
- 2000PhRvC..62d5501D
- Keywords:
-
- 23.40.-s;
- 12.60.-i;
- 14.80.Mz;
- 24.80.+y;
- Beta decay;
- double beta decay;
- electron and muon capture;
- Models beyond the standard model;
- Axions and other Nambu-Goldstone bosons;
- Nuclear tests of fundamental interactions and symmetries;
- Nuclear Experiment
- E-Print:
- 28 pages, 9 figures (LaTeX). Phys. Rev. C (in press)