30.06.2022; Vortrag
Seminar: Searching for Majorana neutrinos with nEXO
01069 Dresden
Despite tremendous progress in understanding the fundamental properties of neutrinos over the past decades, several key questions remain unanswered. In particular, we do not yet know if neutrinos are Majorana particles, i.e., are neutrinos and antineutrinos identical? The most sensitive experimental probe of the Majorana nature of the neutrino is to search for the lepton-number violating neutrinoless double-beta decay (0νββ). A positive observation of this decay mode would confirm that neutrinos are Majorona particles and demonstrate physics that is not explained by the Standard Model. Several collaborations worldwide are searching for 0νββ in different isotopes with various detector technologies, yet, an observation is still outstanding. Sensitivity limits on the half-life of this decay are on the order of 1025 to 1026 years.
In order to increase the sensitivity to 0νββ decays, we are developing a new detector, called nEXO, which will deploy 5 tonnes of liquid xenon, enriched in the isotope 136Xe. To push nEXO’s limit of sensitivity, new technologies, such as Silicon PhotoMultiplier (SiPM), are being developed to achieve an energy resolution of better than 1% at the Q-value. The nEXO detector is designed to improve current measurements by almost two orders of magnitude with a projected sensitivity of 1.35 x 1028 years (90%C.L.), and it is anticipated to be located at SNOLAB. In addition, innovative methods are being investigated to extract and identify the 136Xe ββ-decay daughter 136Ba, which would allow an almost background free measurement of 0νββ. The latter is being developed as a potential upgrade of nEXO.
In this talk I will motivate the search for 0νββ with EXO-200 and nEXO, and present recent technical developments, in particular those of the McGill nEXO group.