Abstract
The isotope is in many ways the best candidate to perform experiments to investigate the value of the electron neutrino mass. It undergoes an electron capture process to with an energy available to the decay, , of about 2.8 keV. According to the present knowledge, this is the lowest value for such transitions. Here we discuss a newly obtained spectrum of , taken by cryogenic metallic magnetic calorimeters with implanted in the absorbers and operated in anticoincident mode for background reduction. For the first time, the atomic deexcitation of the daughter atom following the capture of electrons from the shell in , the OI line, was observed with a calorimetric measurement. The peak energy is determined to be 48 eV. In addition, a precise determination of the energy available for the decay was obtained by analyzing the intensities of the lines in the spectrum. This value is in good agreement with the measurement of the mass difference between and obtained by Penning-trap mass spectrometry, demonstrating the reliability of the calorimetric technique.
- Received 26 April 2017
DOI:https://doi.org/10.1103/PhysRevLett.119.122501
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society