Search for 2 β decay of Cd 106 with an enriched Cd <mml:mprescripts…
2016; American Physical Society; Volume: 93; Issue: 4 Linguagem: Inglês
10.1103/physrevc.93.045502
ISSN2470-0002
AutoresP. Belli, R. Bernabei, V. Brudanin, F. Cappella, V. Caracciolo, R. Cerulli, D. Chernyak, F.A. Danevich, S. d’Angelo, Alessandro Di Marco, A. Incicchitti, M. Laubenstein, V. Mokina, D.V. Poda, O. G. Polischuk, V.I. Tretyak, І.А. Tupitsyna,
Tópico(s)Particle physics theoretical and experimental studies
ResumoA radiopure cadmium tungstate crystal scintillator, enriched in $^{106}\mathrm{Cd}$ to 66%, with mass of 216 g $(^{106}\mathrm{Cd}{\text{WO}}_{4})$, was used to search for double-$\ensuremath{\beta}$ decay processes in $^{106}\mathrm{Cd}$ in coincidence with four ultra-low-background high-purity germanium detectors in a single cryostat. Improved limits on the double-$\ensuremath{\beta}$ processes in $^{106}\mathrm{Cd}$ have been set on the level of ${10}^{20}\ensuremath{-}{10}^{21}$ yr after 13 085 h of data taking. In particular, the half-life limit on the two-neutrino electron capture with positron emission, ${T}_{1/2}^{2\ensuremath{\nu}\ensuremath{\varepsilon}{\ensuremath{\beta}}^{+}}\ensuremath{\ge}1.1\ifmmode\times\else\texttimes\fi{}{10}^{21}$ yr, has reached the region of theoretical predictions. With this half-life limit the effective nuclear matrix element for the $2\ensuremath{\nu}\ensuremath{\varepsilon}{\ensuremath{\beta}}^{+}$ decay is bounded as ${M}_{\mathrm{eff}}^{2\ensuremath{\nu}\ensuremath{\varepsilon}{\ensuremath{\beta}}^{+}}\ensuremath{\le}1.1$. The resonant neutrinoless double-electron captures to the 2718-, 2741-, and 2748-keV excited states of $^{106}\mathrm{Pd}$ are restricted at the level of ${T}_{1/2}\ensuremath{\ge}(8.5\ifmmode\times\else\texttimes\fi{}{10}^{20}\ensuremath{-}1.4\ifmmode\times\else\texttimes\fi{}{10}^{21})$ yr.
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