Bonn 2010 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 28: Astroteilchenphysik II

HK 28.2: Talk

Tuesday, March 16, 2010, 17:00–17:15, HG VI

An alternative route to the neutrino mass: electron capture in ¹⁹⁴Hg — •Christine Böhm — Max-Planck-Institut für Kernphysik, Heidelberg — Ruprecht-Karls-Universität, Heidelberg

The value of the electron neutrino mass is of highest interest as a fundamental number of particle physics as well as an input data for astrophysical and cosmological studies. To determine the neutrino mass, beta-decay sprectra are used typically. Here, an alternative way to determine its upper limit will be presented: by use of the electron capture process of the ¹⁹⁴Hg nucleus. Direct mass measurements of ¹⁹⁴Hg and its daughter nucleus ¹⁹⁴Au were performed at the high-precision Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility (CERN). The mass determination of these nuclei is based on the measurement of the cyclotron frequency ν_cycl=q B/2π m of an ion with charge state q and mass m stored in a Penning trap with the magnetic field B. The Q_EC-value obtained by the mass difference leads to the conclusion that the K-capture is forbidden. However, a measurement using a cryogenic micro-calorimeter is suggested to investigate the de-excitation spectrum of the L-capture in ¹⁹⁴Hg. The comparison of the result of the Penning trap experiment and the micro-calorimetric measurement would lead to the neutrino mass.