Details

Autor(en) / Beteiligte

• Ge, Z
• Eronen, T
• Tyrin, K S
• Kotila, J
• Kostensalo, J
• Nesterenko, D A
• Beliuskina, O
• de Groote, R
• de Roubin, A
• Geldhof, S
• Gins, W
• Hukkanen, M
• Jokinen, A
• Kankainen, A
• Koszorús, Á
• Krivoruchenko, M I
• Kujanpää, S
• Moore, I D
• Raggio, A
• Rinta-Antila, S
• Suhonen, J
• Virtanen, V
• Weaver, A P
• Zadvornaya, A

Titel

{159}Dy Electron-Capture: A New Candidate for Neutrino Mass Determination

Ist Teil von

• Physical review letters, 2021-12, Vol.127 (27), p.272301-272301

Ort / Verlag

United States

Erscheinungsjahr

2021

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• The ground state to ground state electron-capture Q value of ^{159}Dy (3/2^{-}) has been measured directly using the double Penning trap mass spectrometer JYFLTRAP. A value of 364.73(19) keV was obtained from a measurement of the cyclotron frequency ratio of the decay parent ^{159}Dy and the decay daughter ^{159}Tb ions using the novel phase-imaging ion-cyclotron resonance technique. The Q values for allowed Gamow-Teller transition to 5/2^{-} and the third-forbidden unique transition to 11/2^{+} state with excitation energies of 363.5449(14) keV and 362.050(40) keV in ^{159}Tb were determined to be 1.18(19) keV and 2.68(19) keV, respectively. The high-precision Q value of transition 3/2^{-}→5/2^{-} from this work, revealing itself as the lowest electron-capture Q value, is used to unambiguously characterize all the possible lines that are present in its electron-capture spectrum. We performed atomic many-body calculations for both transitions to determine electron-capture probabilities from various atomic orbitals and found an order of magnitude enhancement in the event rates near the end point of energy spectrum in the transition to the 5/2^{-} nuclear excited state, which can become very interesting once the experimental challenges of identifying decays into excited states are overcome. The transition to the 11/2^{+} state is strongly suppressed and found unsuitable for measuring the neutrino mass. These results show that the electron-capture in the ^{159}Dy atom, going to the 5/2^{-} state of the ^{159}Tb nucleus, is a new candidate that may open the way to determine the electron-neutrino mass in the sub-eV region by studying electron-capture. Further experimental feasibility studies, including coincidence measurements with realistic detectors, will be of great interest.