Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 43: Nuclear Structure/Spectroscopy VII
HK 43.2: Gruppenbericht
Donnerstag, 11. März 2004, 17:00–17:30, A
Nuclear matrix elements for two-neutrino double-beta decay — •S. Rakers1, C. Bäumer1, A. van den Berg2, B. Davids2, D. Frekers1, D. De Frenne3, E.-W. Grewe1, P. Haefner1, M.N. Harakeh2, M. Hunyadi2, E. Jacobs3, H. Johansson4, A. Korff1, A. Negret3, L. Popescu3, H. Simon4, and H.J. Wörtche2 — 1Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany — 2Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, NL-9747 AA Groningen, The Netherlands — 3Vakgroep Subatomaire en Stralingsfysica, Universiteit Gent, B-9000 Gent, Belgium — 4Gesellschaft für Schwerionenforschung mbH, D-64291 Darmstadt, Germany
Two-neutrino double-beta (2νββ) decay represents a test-case for our knowledge about the nuclear structure of the involved isobars. The nuclear matrix element relevant for ββ decay can be calculated, if the complete set of Gamow-Teller (GT) matrix elements for the two virtual transitions in the perturbative description are known. Using the 180 MeV deuteron beam at KVI Groningen, we have employed the high-resolution (d,2He) probe to measure the GT+ strength distributions in 48Sc and 116In. These are the intermediate nuclei in the 48Ca and 116Cd ββ decays. By combining our measured GT distributions with the data from a 48Ca(p,n) and a 116Cd(3He,t) experiment [1,2], respectively, we can now compute the double GT matrix element and deduce the 2νββ half-life solely from measured nuclear structure data. [1] B.D. Anderson et al., Phys. Rev. C 31, 1161 (1985).
[2] H. Akimune et al., Phys. Lett. B 394, 23 (1997).