0000000000553799
AUTHOR
S. Nagorny
Evidence of Single State Dominance in the Two-Neutrino Double-β Decay of ^{82}Se with CUPID-0.
We report on the measurement of the two-neutrino double-β decay of ^{82}Se performed for the first time with cryogenic calorimeters, in the framework of the CUPID-0 experiment. With an exposure of 9.95 kg yr of Zn^{82}Se, we determine the two-neutrino double-β decay half-life of ^{82}Se with an unprecedented precision level, T_{1/2}^{2ν}=[8.60±0.03(stat) _{-0.13}^{+0.19}(syst)]×10^{19} yr. The very high signal-to-background ratio, along with the detailed reconstruction of the background sources allowed us to identify the single state dominance as the underlying mechanism of such a process, demonstrating that the higher state dominance hypothesis is disfavored at the level of 5.5σ.
Searches for neutrinoless resonant double electron captures at LNGS
Several experiments were performed during last years at underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (LNGS) of the INFN (Italy) to search for resonant 2$\varepsilon0\nu$ captures in 96Ru, 106Cd, 136Ce, 156Dy, 158Dy, 180W, 184Os, 190Pt with the help of HP Ge semiconductor detectors, and ZnWO4 and 106CdWO4 crystal scintillators. No evidence for r-2$\varepsilon0\nu$ decays was found, and only T_{1/2} limits were established in the range of 10^{14}-10^{21} yr.
Array of cryogenic calorimeters to evaluate the spectral shape of forbidden β-decays : the ACCESS project
The ACCESS (Array of Cryogenic Calorimeters to Evaluate Spectral Shapes) project aims to establish a novel technique to perform precision measurements of forbidden β-decays, which can serve as an important benchmark for nuclear physics calculations and represent a significant background in astroparticle physics experiments. ACCESS will operate a pilot array of cryogenic calorimeters based on natural and doped crystals containing β-emitting radionuclides. In this way, natural (e.g. 113Cd and 115In) and synthetic isotopes (e.g. 99Tc) will be simultaneously measured with a common experimental technique. The array will also include further crystals optimised to disentangle the different backgro…
Charge trapping processes and energy transfer studied in lead molybdate by EPR and TSL
Abstract Charge trapping and energy transfer processes are investigated in PbMoO4 single crystals by electron paramagnetic resonance (EPR) and wavelength-resolved thermally stimulated luminescence (TSL) in a correlated manner. New signals produced by two differently perturbed Mo5+ centers (Mo2 and Mo3) were observed in EPR spectra measured in the crystals after 420 nm light irradiation. Two sets of spin-Hamiltonian parameters, g tensor and the 95,97Mo, 207Pb (super) hyperfine tensors, have been determined and analyzed in terms of crystal field and LCAO-MO theories. A significant overlap of the Mo 5d1 and 6s6p ligand Pb orbitals was deduced for the Mo3 whereas the Mo2 center seemed to be not…
Latest results from CUPID-0
International audience; CUPID-0 is a pilot experiment in scintillating cryogenic calorimetry for the search of neutrino-less double beta decay. 26 ZnSe crystals were operated continuously in the first project phase (March 2017 - December 2018), demonstrating unprecedented low levels of background in the region of interest at the Q-value of $^{82}\rm{Se}$. From this successful experience comes a demonstration of full alpha to beta/gamma background separation, the most stringent limits on the $^{82}\rm{Se}$ neutrino-less double beta decay, as well as the most precise measurement of the $^{82}$Se half-life. After a detector upgrade, CUPID-0 began its second and last phase (June 2019 - February…