Bonn 2010 – wissenschaftliches Programm
HK 28.2: Vortrag
Dienstag, 16. März 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 νcycl=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 QEC-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.