The Status and Initial Results of the MAJORANA DEMONSTRATOR Experiment

TL;DR

The MAJORANA DEMONSTRATOR aims to detect neutrinoless double-beta decay using high purity germanium detectors, establishing background levels and scalability for future large-scale experiments, with initial results indicating progress in these goals.

Contribution

This paper reports the initial results and status of the MAJORANA DEMONSTRATOR, demonstrating its background levels and readiness for next-generation neutrinoless double-beta decay searches.

Findings

Initial physics runs show low-background data collection

The detector modules are operational and stable

The experiment's setup is scalable for larger future detectors

Abstract

Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The MAJORANA Collaboration assembled an array of high purity Ge detectors to search for neutrinoless double-beta decay in Ge-76. The MAJORANA DEMONSTRATOR is comprised of 44.1 kg (29.7 kg enriched in Ge-76) of Ge detectors divided between two modules contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota, USA. The initial goals of the DEMONSTRATOR are to establish the required background and scalability of a Ge-based next-generation ton-scale experiment. Following a commissioning run that started in 2015, the first detector module started low-background data production in early 2016. The second detector module was added in August 2016 to begin operation of the entire array. We discuss results of the initial physics runs, as well as the status and physics reach of the full MAJORANA DEMONSTRATOR experiment.