AMoRE searches for the neutrinoless double beta decay using 100 kg of enriched ^{100}Mo. Scintillating molybdate crystals coupled with a metallic magnetic calorimeter operate at milli-Kelvin temperatures to measure the energy of electrons emitted in the decay. AMoRE-I is a demonstrator for the full-scale AMoRE, operated at the Yangyang Underground Laboratory for over two years. The exposure was 8.02 kg year (or 3.89 kg_{^{100}Mo} year), and the total background rate near the Q value was 0.025±0.002 counts/keV/kg/year. We observed no indication of 0νββ decay and report a new lower limit of the half-life of ^{100}Mo 0νββ decay as T_{1/2}^{0ν}>2.9×10^{24} yr at 90% confidence level. The effective Majorana mass limit range is m_{ββ}<(210-610) meV using nuclear matrix elements estimated in the framework of different models, including the recent shell model calculations.

The LEGEND Collaboration is searching for neutrinoless double-beta ( 0 ν β β ) decay by operating high-purity germanium detectors enriched in Ge 76 in a low-background liquid argon environment. Building on key technological innovations from the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first 0 ν β β decay search based on 61.0 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of 0.5 − 0.2 + 0.3 cts / ( keV ton yr ) in the 0 ν β β decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of 2.8 × 10 26 yr on the half-life of 0 ν β β decay, reveals no evidence for a signal and sets a new observed lower limit at T 1 / 2 0 ν > 1.9 × 10 26 yr (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range m β β < 75 – 200 meV , depending on the adopted nuclear matrix element.

RED-100 is a two-phase liquid xenon time projection chamber with an active volume containing 126 kg of liquid xenon. The detector was exposed to an antineutrino flux of about 1.4 × 10 13 cm − 2 s − 1 at a distance of 19 m from the 3.1 GW Kalinin nuclear power plant reactor core. The comparison of data from 331 kg · days with the reactor on and 106 kg · days with the reactor off shows no statistically significant excess and the constraint on coherent elastic scattering of antineutrinos off xenon nuclei cross section is given.

The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0 nu beta beta) in Ge-76, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). In the first phase of the experiment, a 90% confidence level (C.L.) sensitivity of 2.4 . 10(25) yr on the 0 nu beta beta decay half-life was achieved with a 21.6 kg.yr exposure and an unprecedented background index in the region of interest of 10(-2) counts/(keV.kg.yr). No excess of signal events was found, and an experimental lower limit on the half-life of 2.1 . 10(25) yr (90% C.L.) was established. Correspondingly, the limit on the effective Majorana neutrino mass is m(ee) < 0.2-0.4 eV, depending on the considered nuclear matrix element. The previous claim for evidence of a 0 nu beta beta decay signal is strongly disfavored, and the field of research is open again