KATRIN: Status and Prospects for the Neutrino Mass and Beyond
  The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a
high-precision integral spectrum of the endpoint region of T2 beta decay, with
the primary goal of probing the absolute mass scale of the neutrino. After a
first tritium commissioning campaign in 2018, the experiment has been regularly
running since 2019, and in its first two measurement campaigns has already
achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design
sensitivity is 0.2 eV at the 90% confidence level. In this white paper we
describe the current status of KATRIN; explore prospects for measuring the
neutrino mass and other physics observables, including sterile neutrinos and
other beyond-Standard-Model hypotheses; and discuss research-and-development
projects that may further improve the KATRIN sensitivity.
