NPA Seminar (virtual): Jan Behrens, KIT, “The KATRIN experiment: The Challenge of Determining the Absolute Neutrino Mass”

The KArlsruhe TRItium Neutrino experiment probes the absolute neutrinomass scale via the β-decay kinematics of molecular tritium. With a sensitivity goal of 0.2 eV/c² at 90% CL, it provides model-independent input to both particle theory and cosmology. The source is highly pure, cryogenic T₂ gas. The electrons resulting from β-decay are guided along magnetic field lines toward a high-resolution, integrating spectrometer for
energy analysis. A silicon detector counts β-electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise mapping of the spectral tail with an endpoint energy of 18.6 keV.
The analysis of our first measurement in 2019 established an upper limit of 1.1 eV on the neutrino-mass scale at 90% CL. This result, based on a few weeks of data-taking at a reduced source intensity and dominated by
statistical uncertainty, improves on prior limits by nearly a factor of two. Future KATRIN measurements in the following years will benefit from improved systematic and statistical uncertainties to reach the final sensitivity goal.