Speaker
Description
The main goal of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso (LNGS, Italy) is the search for the lepton-number-violating neutrinoless double-beta ($0\nu\beta\beta$) decay of 76Ge. The potential discovery of such phenomenon would have significant implications in cosmology and particle physics, unrevealing the Majorana nature of neutrinos. The main feature of the Gerda design consisted in operating an array of bare germanium diodes enriched in 76Ge in an active liquid argon shield. Phase II physics run (December 2015 - November 2019) reached an unprecedentedly low background index of $5.2 \times 10^{−4}$ 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 0νββ decay in 76Ge was set at $T_{1/2} > 1.8 \times 10^{26}$ 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 76Ge double-beta decays searches with and without neutrinos, and recent results on searches for tri-nucleon decay of 76Ge and search for new exotics physics.
| Collaboration / Activity | GERDA |
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