First results from GERDA neutrinoless double beta decay There was a previous claim to see 0nubeta-beta in Germanium in PLB 586-198(2004). GERDA is testing this claim with a low background Germanium detector in Gran Sasso. With 21.6 kg-yr of data, they see 3 (0) events in +-2 (+-1) sigma of the expected value, with 5.9 signal and 2.0 BG expected. They rule out the previous claim (aka Klapdor) with high probability. The lower limit on the half life is 2.1 e25 years (90%CL) corresponding to an upper limit on the effective electron nu mass "mee" < 0.2-0.4 eV (depending on matrix elements). mpi-hd.mpg.de/gerda/public. eps-hep2013.eu/press/pressReleases/GERDA0720.html
Posted on: Thu, 01 Aug 2013 14:36:45 +0000
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