David Wark

Abstract:

The neutron electric dipole moment (EDM) experiment at the Institut Laue-Langevin (ILL) has completed data taking and subsequently the systematic errors have been evaluated. In this paper the experimental technique is discussed and results of the experiment are given. The experiment is based on a precision measurement of the Larmor precession frequency of neutrons in a magnetic field and employs a cohabiting mercury magnetometer. We have reached a final statistical precision of 1.5 × 10-26 e cm, the systematic potential for error, dominated by geometric phase shifts due to magnetic field inhomogeneities in the experiment, is found to be of the same order as the statistical precision obtained.

Abstract:

With the evidence for massive neutrinos from recent ν-oscillation experiments, one of the most fundamental tasks of particle physics over the next years will be the determination of the absolute mass scale of neutrinos, which has crucial implications for cosmology, astrophysics and particle physics. The KArlsruhe TRItium Neutrino (KATRIN) experiment is the next-generation direct neutrino mass experiment with a sensitivity to sub-eV ν-masses. It combines an ultra-luminous molecular windowless gaseous tritium source with a high resolution electrostatic retarding spectrometer (MAC-E filter) to measure the spectral shape of β-decay electrons close to the endpoint at 18.6 keV with unprecedented precision. If no neutrino mass signal is found, the KATRIN sensitivity after 3 years of measurements is mν < 0.2 eV/c2 (90 % CL.); a ν-mass signal of mν = 0.35 (0.30) eV/c2 can be measured with 5 (3) σ evidence.