New results of 116 Cd double β decay study with 116 CdWO 4 scintillators

摘要: A new phase of a ${}^{116}\mathrm{Cd}$ double \ensuremath{\beta} decay experiment is in progress the Solotvina Underground Laboratory. Four enriched ${}^{116}{\mathrm{CdWO}}_{4}$ scintillators with total mass 339 g are used setup, whose active shield made 15 natural ${\mathrm{CdWO}}_{4}$ crystals (20.6 kg). The background rate energy interval 2.5--3.2 MeV 0.03 counts/yr kg keV. half-life for 2\ensuremath{\nu}2\ensuremath{\beta} measured as ${T}_{1/2}(2\ensuremath{\nu})=2.6\ifmmode\pm\else\textpm\fi{}0.1(\mathrm{stat}{)}_{\ensuremath{-}0.4}^{+0.7}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{19}$ yr. ${T}_{1/2}$ limits neutrinoless 2\ensuremath{\beta} set at ${T}_{1/2}g~0.7(2.5)\ifmmode\times\else\texttimes\fi{}{10}^{23}$ yr 90%(68%) C.L. transition to ground state ${}^{116}\mathrm{Sn},$ while decays first ${2}_{1}^{+}$ and second ${0}_{1}^{+}$ excited levels ${}^{116}\mathrm{Sn}$ ${T}_{1/2}g~1.3(4.8)\ifmmode\times\else\texttimes\fi{}{10}^{22}$ $g~0.7(2.4)\ifmmode\times\else\texttimes\fi{}{10}^{22}$ C.L., respectively. For 0\ensuremath{\nu}2\ensuremath{\beta} emission one or two Majorons, ${T}_{1/2}(0\ensuremath{\nu}M1)g~3.7(5.8)\ifmmode\times\else\texttimes\fi{}{10}^{21}$ ${T}_{1/2}(0\ensuremath{\nu}M2)g~5.9(9.4)\ifmmode\times\else\texttimes\fi{}{10}^{20}$ Restrictions on value neutrino mass, right-handed admixtures weak interaction, neutrino-Majoron coupling constant derived ${m}_{\ensuremath{\nu}}l~2.6(1.4)$ eV, $\ensuremath{\eta}l~3.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8},$ $\ensuremath{\lambda}l~3.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ ${g}_{M}l~12(9.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$