A pr 2 01 6 Direct determination of the atomic mass difference of 187 Re and 187 Os for neutrino physics and cosmochronology

D.A. Nesterenko, 2 S. Eliseev, K. Blaum, M. Block, S. Chenmarev, 4 A. Dörr, C. Droese, 6 P.E. Filianin, 4 M. Goncharov, E. Minaya Ramirez, Yu.N. Novikov, 2, 4 L. Schweikhard, and V.V. Simon 6 Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany Petersburg Nuclear Physics Institute, Gatchina, 188300 St. Petersburg, Russia GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany Physics Faculty of St.Petersburg State University, 198904, Peterhof, Russia Institut für Physik, Ernst-Moritz-Arndt-Universität, 17487 Greifswald, Germany Helmholtzinstitut Mainz, 55099 Mainz, Germany For the first time a direct determination of the atomic mass difference of Re and Os has been performed with the Penning-trap mass spectrometer SHIPTRAP applying the novel phaseimaging ion-cyclotron-resonance technique. The obtained value of 2492(30stat)(15sys) eV is in excellent agreement with the Q-values determined indirectly with microcalorimetry and thus resolves a long-standing discrepancy with older proportional counter measurements. This is essential for the determination of the neutrino mass from the β−-decay of Re as planned in the future microcalorimetric measurements. In addition, an accurate mass difference of Re and Os is also important for the assessment of Re for cosmochronology.