Direct neutrino mass measurement at the KATRIN experiment

The KArlsruhe TRItium Neutrino experiment (KATRIN) is performing a high precision spectroscopy of the tritium beta-decay spectrum to search for the signature of the neutrino mass. It combines a high-intensity gaseous molecular tritium source and a high-resolution electrostatic spectrometer with magnetic adiabatic collimation. This allows KATRIN to reach a sub-eV sensitivity to the neutrino mass. Moreover, existence of the fourth neutrino-mass eigenstate (sterile neutrino), a new light boson and exotic general weak interactions are investigated. The analysis of the first five KATRIN measurement campaigns results in a new neutrino-mass upper limit m_<0. 45 \, eV at 90% confidence level (CL) and the existence of a sterile neutrino is excluded in the studied region with 95% CL. In the analysis of the second measurement campaign we derive competitive constrains on general neutrino interactions and evaluate the campaign's sensitivity to the existence of the new light bosons.