The KArlsruhe TRItium Neutrino (KATRIN) collaboration aims to measure the neutrino mass by precision spectroscopy of tritium $\beta$-decay with 0.2$\,$eV target sensitivity. Recently, KATRIN has improved the upper bound on the effective electron-neutrino mass to 0.8$\,$eV at 90$\,$% confidence level [1].
Probing the neutrino mass is the main purpose of the KATRIN experiment. Beyond this, the ultra-precise measurement of the $\beta$-spectrum can be used for new physics searches. We report on the investigations and results on the neutrino mass, as well as on Lorentz Invariance Violations, Light Sterile Neutrinos, and General Neutrino Interactions.
[1] KATRIN Coll., Nat. Phys., “Direct neutrino-mass measurement with sub-electronvolt sensitivity”.