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Статья

Arnquist, I.J.
Constraints on the Decay of &sup(180m)Ta / I.J.Arnquist, S.Vasilyev, [et al.] // Physical Review Letters [Electronic resource]. – 2023. – Vol.131, No.15. – P. 152501. – URL: https://doi.org/10.1103/PhysRevLett.131.152501. – Bibliogr.: 54.

&sup(180⁢m)Ta is a rare nuclear isomer whose decay has never been observed. Its remarkably long lifetime surpasses the half-lives of all other known *b and electron capture decays due to the large K-spin differences and small energy differences between the isomeric and lower-energy states. Detecting its decay presents a significant experimental challenge but could shed light on neutrino-induced nucleosynthesis mechanisms, the nature of dark matter, and K-spin violation. For this study, we repurposed the Majorana Demonstrator, an experimental search for the neutrinoless double-beta decay of *7*6Ge using an array of high-purity germanium detectors, to search for the decay of &sup(180⁢m)Ta. More than 17 kg, the largest amount of tantalum metal ever used for such a search, was installed within the ultralow-background detector array. In this Letter, we present results from the first year of Ta data taking and provide an updated limit for the 180mTa half-life on the different decay channels. With new limits up to 1.5 × 10*1*9 yr, we improved existing limits by 1–2 orders of magnitude which are the most sensitive searches for a single *b and electron capture decay ever achieved. Over all channels, the decay can be excluded for T&sub(1/2) < 0.29 × 1018 yr



Спец.(статьи,препринты) = С 341.2в1 - Изомеры и метастабильные состояния. Высокоспиновые состояния
Спец.(статьи,препринты) = С 341.3 - Деление ядер
ОИЯИ = ОИЯИ (JINR)2023