Search for Pauli Exclusion Principle Violating Atomic Transitions and Electron Decay with a P-type Point Contact Germanium Detector

TL;DR

This paper reports a search for violations of the Pauli Exclusion Principle and electron decay using germanium detectors, setting new lower limits on transition lifetimes and discussing future improvements with the MAJORANA DEMONSTRATOR.

Contribution

First experimental limits on Pauli-exclusion-violating atomic transitions and electron decay using p-type point contact germanium detectors.

Findings

Lower limit on transition lifetime: 5.8x10^30 seconds

Lower limit on electron decay: 6.8x10^30 seconds

Future experiments could improve limits by an order of magnitude

Abstract

A search for Pauli-exclusion-principle-violating K-alpha electron transitions was performed using 89.5 kg-d of data collected with a p-type point contact high-purity germanium detector operated at the Kimballton Underground Research Facility. A lower limit on the transition lifetime of 5.8x10^30 seconds at 90% C.L. was set by looking for a peak at 10.6 keV resulting from the x-ray and Auger electrons present following the transition. A similar analysis was done to look for the decay of atomic K-shell electrons into neutrinos, resulting in a lower limit of 6.8x10^30 seconds at 90 C.L. It is estimated that the MAJORANA DEMONSTRATOR, a 44 kg array of p-type point contact detectors that will search for the neutrinoless double-beta decay of 76-Ge, could improve upon these exclusion limits by an order of magnitude after three years of operation.