Speaker: Ralph Massarczyk



From MAJORANA to LEGEND - the search for neutrinoless double beta decay in Germanium




Searches for neutrinoless double-beta decay test the Majorana nature of the neutrino and can give us a hint about mass hierarchy of the neutrinos.

The MAJORANA Demonstrator is an array of germanium detectors to search for this process in 76Ge with the goal to show that it is possible to establish the required background levels for a next-generation ton-scale experiment. Forty-four kilogram of high-purity Ge (HPGe) detectors are split in two modules and contained in a ultra low-background shield a mile underground at the Sanford Underground Research Facility in Lead,  South Dakota. The full detector array is its final configuration and has been acquiring data since 2016.

I will discuss the status of the MAJORANA Demonstrator and show the results from the first physics run; including current background estimates and the resulting half-lime limit for neutrinoless double-beta decay. Finally, I will give an outlook on the LEGEND collaboration which brings together physicists from the existing germanium-based experiments MAJORANA (US-led), GERDA (Europe), CDEX (China), and others with the goal to build a ton-scale germanium array to search for neutrinoless double beta decay. 

I will present a short overview on the physics goals as well as the impact of LANL in the realization of this project.