Münster 2017 – wissenschaftliches Programm
T 48.2: Eingeladener Vortrag
Dienstag, 28. März 2017, 14:27–14:54, H 3
The search for neutrinoless double beta decay with EXO-200 and nEXO — •Thilo Michel — Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-Universität Erlangen-Nürnberg
Are neutrinos Dirac- or Majorana-fermions? Still today, this question has not been answered although huge efforts have been made to search for neutrinoless double beta decay which is the most practical way to get an answer. Furthermore, a possible detection of this decay could give valuable information about the masses of the neutrino mass eigenstates as the half-life depends on the effective Majorana neutrino mass. The Enriched Xenon Observatory EXO-200 has carried out one of the most sensitive searches for this decay channel in 136Xe with two years of data. The EXO-200 detector is a double-sided, single-phase liquid xenon time-projection-chamber. EXO-200 started a second phase of data taking in April 2016. The next-generation, tonne-scale experiment nEXO is the successor of EXO-200. With its single-sided, single-phase time-projection-chamber filled with 5 tonnes of enriched liquid xenon nEXO will be able to probe the possible effective Majorana neutrino masses in the inverted mass hierarchy regime. Light-detection in nEXO will be carried out with silicon photomultipliers. The charge measurement will be realized with a checkerboard style electrode matrix. With the projected energy resolution of 1% (σ) at the Q-value of the decay, nEXO aims at a half-life sensitivity of 6.2×1027 years at 90% C.L. after 5 years of measuring time. In this talk, the EXO-200 experiment and the development of nEXO will be presented.