Session DN: Neutrino Physics I

Status of the KATRIN Experiment

The Karlsruhe Tritium Neutrino (KATRIN) experiment investigates the effective electron anti-neutrino mass with tritium beta decays at a sensitivity of 0.2 eV (90% CL). This measurement approach to probe the neutrino mass scale is model independent, unlike cosmological fits or neutrinoless double beta decay experiments. The KATRIN experiment 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 under extensive commissioning and first tritium was injected in May 2018. In this talk, the principle and experimental challenges of the neutrino mass measurement with KATRIN, as well as the current status of the experiment, will be presented.   

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

Neutrino flavor oscillation experiments prove that neutrinos do have non- zero 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. A highest precision measurement of the β⁻-decay spectrum of tritium around its endpoint region (Q = 18.6 keV) can reveal the antielectron neutrino mass m_ν. The current state of the art experiment stretches all technological limits to probe m_ν  down to 200 meV/c². The Project 8 collaboration envisions a completely new path to measure m_ν. The recently demonstrated technique of Cyclotron Radiation Emission Spectroscopy (CRES) allows for a frequency-based measurement of the decay electron energy. I will present this new approach and the collaboration’s staged approach to devise an experiment that combines CRES with an atomic tritium source to achieve a neutrino mass sensitivity of 40meV/c², below the minimum mν ̄e allowed for the inverted neutrino mass ordering scheme.   

Project 8 Phase III Design Progress

Project 8 is a tritium endpoint experiment to measure the mass of the neutrino using
the technique of Cyclotron Radiation Emission Spectroscopy (CRES).  Early phases
(I and II) of Project 8 demonstrated CRES in small volumes confined by microwave
waveguides.  An immediate goal for future phases is to scale the detection scheme
in size to accommodate sufficient tritium source intensity for a competitive neutrino
mass measurement.  We present progress on the conceptual design for CRES experiments
conducted in a free space radiation environment, focusing on simulation work that 
will guide the development of advanced signal processing and data acquisition 
techniques integral to Project 8.  Details of electron trapping and radiation 
detection schemes are discussed in terms of feasibility and their implications for 
the third phase of Project 8, intended to be competitive with current
limits on neutrino mass from the Mainz and Troitsk experiments (m_ν ≤ 2 eV).   

Requirements for the final phase of Project 8

Project 8 is an atomic tritium-based experiment to directly measure the mass of the electron anti-neutrino via cyclotron radiation emission spectroscopy. We have adopted a four-phase approach to the measurement, with the final phase having a sensitivity goal of 40 meV. This sensitivity will allow us to either make a positive measurement of the mass or distinguish between normal and inverted neutrino mass ordering. In this presentation we will lay out the broad requirements to meet the scientific goals of Phase IV. We will also provide some details on our efforts to demonstrate key technologies, including the production / cooling / purification of atomic tritium, the design and testing of a magnetic trap for the atoms, methods to observe the femtowatt-scale cyclotron radiation, quantum-limited low-noise amplifiers, and data reduction.