Particle and Astroparticle Physics Seminar

First results of the KATRIN experiment on an absolute neutrino mass measurement

Björn Lehnert

Lawrence Berkeley National Laboratory

Since the Nobel prize-winning discovery of neutrino oscillation, we know that neutrinos have a non-zero mass. However, the absolute mass scale of the most abundant matter particle in the Universe remains unknown. Three fundamentally different approaches aim to determine the neutrino mass: Global fits to cosmological data, neutrinoless double beta decay and kinematic measurements. The latter is the most direct way to determine the mass of the neutrino and is investigated with tritium beta decays in the Karlsruhe Tritium Neutrino (KATRIN) experiment.

KATRIN performs spectroscopy of beta-electrons near the tritium endpoint at 18.6 keV by employing a high intensity windowless gaseous tritium source and a high-precision electrostatic spectrometer based on the MAC-E filter principle. The required sensitivity demands novel hardware operating with unprecedented stability, and a precise understanding of all systematic effects and their correlations. The experiment has been planned and constructed for more than 18 years and completed its first measurement campaign in spring this year. One month ago, the first results were released. In this seminar, I will introduce the KATRIN experiment and its kinematic measurement approach within the larger picture of neutrino mass measurements. I will then present the first results of KATRIN and its overall future potential.