Observation of Two-Neutrino Double-Beta Decay in ^136Xe: First EXO Results in the Search for the Neutrino-less decay
Jacques A. Farine
The Enriched Xenon Observatory (EXO) collaboration has observed the two-neutrino double beta decay of ^136Xe with EXO-200, a prototype to the EXO detector in development. This second order process, predicted by the Standard Model, has been observed for several nuclei but not for ^136Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrino-less double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale. The EXO-200 detector and underground site at WIPP, New Mexico, will be presented, and the observation of the two-neutrino decay discussed. The experimental efforts in the filed will be highlighted, with comments on the calculations of nuclear matrix elements. The development of EXO will be discussed: a multi-tonne detector with daugther ion identification as a powerful background suppression tool, with SNOLAB a possible site.
Date: Wednesday, 4 April 2012 Time: 14:30 Where: McGill University Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103) Contact: Robert Rutledge