Project 8: A frequency-based approach to measure the absolute neutrino mass scale

Neutrino flavor oscillation experiments prove that neutrinos do have nonzero masses. Extensions to the Standard Model of Particle Physics have been developed to explain the non-zero masses and can be directly tested by a measurement of the absolute neutrino mass scale. The mass of the electron antineutrino can be determined from the highest precision measurement of the beta-decay spectrum of tritium around its endpoint region (Q = 18.6 keV). The current state of the art experiment stretches all technological limits to probe the range of the electron antineutrino mass down to 200meV. A completely new path has to be envisioned to test the full range of electron neutrino masses allowed in the inverted neutrino mass ordering scheme. The Project 8 collaboration has recently demonstrated the novel technique of Cyclotron Radiation Emission Spectroscopy (CRES) to pursue a frequency-based measurement approach. I will present this new approach and results obtained with mono-energetic conversion electrons from 83m^Kr. The phased program towards a measurement using atomic tritium with a mass sensitivity potentially below 40meV will be discussed as well as the application of CRES to high energy beta-decays in searches for exotic, tensor-like interactions.

Financial support by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics to the University of Washington under Award Number DE-FG02-97ER41020 is acknowledged.