Search for the decay of nature's rarest isotope ${}^{180m}$Ta

Abstract

${}^{180m}$Ta is the rarest naturally occurring quasi-stable isotope and the longest lived metastable state which is known. Its possible decay via the ${\beta }^{-}$ or the electron capture channel has never been observed. This article presents a search for the decay of ${}^{180m}$Ta with an ultra low background Sandwich HPGe gamma spectrometry setup in the HADES underground laboratory. No signal is observed and improved lower partial half-life limits are set with a Bayesian analysis to $5.8\cdot 10^{16}$ yr for the ${\beta }^{-}$ channel and $2.0\cdot 10^{17}$ yr for the electron capture channel (90% credibility). The total half-life of ${}^{180m}$Ta is longer than $4.5\cdot 10^{16}$ yr. This is more than a factor of two improvement compared to previous searches.

References in corpus (2)

• Survival of Nature's Rarest Isotope 180Ta under Stellar Conditions
• Reanalysis of the (J = 5) state at 592 keV in 180Ta and its role in the neutrino-process nucleosynthesis of 180Ta in supernovae

Cited by in corpus (10)

• Atlas of Nuclear Isomers -- Second Edition
• Metastable Nuclear Isomers as Dark Matter Accelerators
• Experimental searches for rare alpha and beta decays
• Search for dark matter induced de-excitation of ${}^{180}$Ta${}^{\mathrm{m}}$
• Constraints on the decay of ${}^{180m}$Ta
• First direct observation of isomeric decay in neutron-rich odd-odd ${}^{186}$Ta
• Deep-underground search for the decay of 180m-Ta with an ultra-low-background HPGe detector
• Search for Electron Capture in ${}^{176}$Lu with LYSO scintillator
• Beta decays in investigations and searches for rare effects
• Dark Matter Search with the Nuclear Isomer Ta-180m