Dr Magnus Schlösser (Karlsruhe Institute of Technology)
The Karlsruhe Tritium Neutrino (KATRIN) experiment probes the effective electron anti-neutrino mass, mν, via a high-precision measurement of the tritium β-decay spectrum close to its endpoint at 18.6keV. In this talk I present the second physics run. The source activity was increased by a factor of 3.8 and the background was reduced by 25% with respect to the first campaign. A sensitivity on mν of 0.7eV/c2 at 90% confidence level (CL) was reached. This is the first sub-eV sensitivity from a direct neutrino-mass experiment. The best fit to the spectral data yields m2ν=(0.26±0.34)eV2/c4, resulting in an upper limit of mν<0.9eV/c2 (90% CL). By combining this result with the first neutrino mass campaign, we find an upper limit of mν<0.8eV/c2 (90% CL).
