Speaker: Ralph Massarczyk

P-23: NEUTRON SCIENCE & TECHNOLOGY

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

Abstract: 

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.