The Majorana Demonstrator Status and Preliminary Results

TL;DR

The Majorana Demonstrator uses high-purity germanium detectors to search for neutrinoless double-beta decay, aiming to determine the Majorana nature of neutrinos and measure their mass, with preliminary results indicating promising detector performance.

Contribution

This paper reports on the construction, operation, and initial findings of the Majorana Demonstrator, a novel experiment employing high-purity Ge detectors for neutrinoless double-beta decay search.

Findings

Achieved 2.5 keV energy resolution at Qββ

Successfully constructed and operated 44.1 kg of Ge detectors

Started physics data collection in 2016

Abstract

The Majorana Collaboration is using an array of high-purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. Searches for neutrinoless double-beta decay are understood to be the only viable experimental method for testing the Majorana nature of the neutrino. Observation of this decay would imply violation of lepton number, that neutrinos are Majorana in nature, and provide information on the neutrino mass. The Majorana Demonstrator comprises 44.1 kg of p-type point-contact Ge detectors (29.7 kg enriched in 76Ge) surrounded by a low-background shield system. The experiment achieved a high efficiency of converting raw Ge material to detectors and an unprecedented detector energy resolution of 2.5 keV FWHM at Q$_{\beta\beta}$. The Majorana collaboration began taking physics data in 2016. This paper summarizes key construction aspects of the Demonstrator and shows preliminary results from initial data.