Beyond the Standard Model Searches with the Majorana Demonstrator Experiment

TL;DR

The Majorana Demonstrator uses high-purity germanium detectors to search for neutrinoless double beta decay and solar axions, achieving low background levels and excellent energy resolution to explore physics beyond the Standard Model.

Contribution

This work reports the first search for solar axions using the Majorana Demonstrator's high-purity germanium detectors and a novel detection method leveraging Bragg condition correlations.

Findings

Achieved low background levels and high energy resolution in the detector array.

Conducted the first solar axion search with this detector setup.

Provided competitive constraints on axion-photon coupling.

Abstract

The Majorana Demonstrator experiment operated two modular arrays of p-type point contact high purity germanium (HPGe) detectors, of which 30 kg is enriched to 88% in Ge-76, to search for neutrinoless double beta decay. The data-taking campaign for double beta decay with enriched detectors was successfully concluded in March 2021, and data-taking with natural detectors is still ongoing. The Demonstrator has achieved excellent energy performance in a wide dynamic range covering 1 keV to 10 MeV. The extra-low background level and excellent energy performance achieved by the Demonstrator makes it competitive in various searches of physics beyond the Standard Model. If there is an axion-photon coupling, axions can be produced by the Primakoff conversion of photons in the Sun. Solar axions can inversely generate photon signals in germanium crystals, which can be coherently enhanced when the Bragg condition is satisfied. The Demonstrator is searching for solar axions with a novel method to correlate and leverage its high number of HPGe detectors. In this talk, we will discuss the status and results of recent searches for new physics with the Demonstrator, including the first reporting of a solar axion search.