PoS - Proceedings of Science
Volume 449 - The European Physical Society Conference on High Energy Physics (EPS-HEP2023) - T04 Neutrino Physics
Latest results from GERDA Phase II experiment on 76Ge double-beta decay and exotic decay searches
A. Garfagnini*  on behalf of the GERDA Collaboration
Full text: pdf
Pre-published on: January 30, 2024
Published on: March 21, 2024
The GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso (LNGS, Italy) had, as main goal, the search for the lepton-number-violating neutrinoless double-beta ($0\nu\beta\beta$) decay of $^{76}$Ge. The potential discovery of such phenomenon would have significant implications in cosmology and particle physics, helping unrevealing the Majorana nature of neutrinos. The main feature of the GERDA design consisted in operating an array of bare germanium diodes enriched in $^{76}$Ge in an active liquid argon shield. The Phase II physics run (December 2015 - November 2019) reached an unprecedentedly low background index of $5.2 \times 10^{-4}~\mbox{counts/(keV kg yr)}$ in the signal region, collecting an exposure of 103.7~kg~yr while operating in a background-free regime. No signal was observed after a total exposure of 127.2~kg~yr for a combined analysis of Phase I (November 2011 - September 2013) and Phase II data. A lower bound on the half-life of $0\nu\beta\beta$ decay in $^{76}$Ge was set at $T_{1/2} > 1.8 \times 10^{26}~\mbox{yr}$ (90\% C.L.), which coincides with the median expectation under the no signal hypothesis.
This contribution will review the GERDA experiment design and its final results, both on $^{76}$Ge double-beta decay searches with and without neutrinos, and recent results on searches for tri-nucleon decay of $^{76}$Ge and search for new exotics physics.
DOI: https://doi.org/10.22323/1.449.0158
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