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Information × Registration Number 0223U004867, 0123U102652 , R & D reports Title Double beta decay of atomic nuclei popup.stage_title Head Kobychev Vladyslav V., Кандидат фізико-математичних наук Registration Date 06-12-2023 Organization Institute of Nuclear Research of the National Academy of Sciences of Ukraine popup.description2  A new half-life limit T1/2 > 1.8 × 1024 yr is set for the 0ν2β decay of 100Mo, that corresponds to one of the strongest effective Majorana neutrino mass limits <m> < 0.28–0.49 eV. The half-life of 100Mo relative to the 2ν2β decay to the ground state of 100Ru is determined with the highest accuracy ±1.6%, the 2ν2β transition to the first 0+ excited level of 100Ru is observed with T1/2=(7.5±0.8(stat.)+0.4-0.3(syst.))×1020 yr. New lower limits for the half-lives of 106Cd, 100Mo, 150Nd, 184Os, 192Os, 190Pt, 198Pt relative to different channels and modes of the 2β decay were set on the level of T1/2 > (1014 - 1022) yr. The half-life of 150Nd relative to the 2ν2β transition to the first excited 0+ level of 150Sm is measured in two independent experiments as T1/2=(1.11+0.19-0.14(stat.)+0.17-0.15(syst.)) ×1020 yr (NEMO-3 tracking detector) and T1/2=(0.73+0.18-0.11(stat.)+0.16-0.17(syst.))×1020 yr (HPGe γ spectrometry). An evidence of the axial-vector coupling constant gA quenching with a factor of 0.655(2) as compared to the free-nucleon value gA = 1.276 is obtained with a high-resolution LiInSe2 bolometer. The half-life and beta-spectrum shape of 113mCd were measured, an optimized experiment to determine the 50V decay scheme was developed, to derive independent estimations of the constant gA. Low background detectors for study of double beta decay of 100Mo and 106Cd, naturally occurring zinc and tungsten nuclides, search for dark matter, detection of neutrino from supernova were developed and tested. New limits were set for α and 2α decay of the naturally occurring nuclides of neodymium and osmium on the level of T1/2 > 1016-1021 yr, the half-life of 190Pt relative to the α decay to the first excited level of the daughter was set as T1/2=(2.28+0.19-0.16(stat.) ±0.9(syst.))×1014 yr. A new upper limit on atomic abundance of hypothetical naturally occurring long-lived seaborgium (eka-tungsten, Z = 106) in tungsten was set as 5.1 × 10−15 atom (Sg) / atom (W). Product Description popup.authors Danevych Fedir A. Zarytskyi Mykola M Kasperovych Dmytro V. Klavdienko Volodymyr R Sokur Nazar V Tretyak Volodymyr I. popup.nrat_date 2023-12-06 Close