Latest results of the Mainz Neutrino Mass Experimen

The Mainz Neutrino Mass Experiment investigates the endpoint region of the tritium β decay spectrum very precisely to extract the rest mass of the electron antineutrino. The measurements are performed with a MAC-E-Filter, combining [InlineMediaObject not available: see fulltext.]agnetic [InlineMediaObject not available: see fulltext.]diabatic [InlineMediaObject not available: see fulltext.]ollimation and an [InlineMediaObject not available: see fulltext.]lectrostatic high pass Filter. After optimal preparation of the apparatus very stable and high quality data have been taken in 2001, which do not show any residual problem. A combined analysis of data from 1998/1999 and 2001 lead to the final value of m ν 2 = –0.7 ± 2.2 stat ± 2.1 sys eV2/c4, leading to an upper limit m ν ≤ 2.3 eV/c2 (95% C.L.). PACS: 14.60.P Neutrinos, mass and mixing – 23.40 β deca