Speaker
Description
The search for neutrinoless double beta (0$\nu\beta\beta$) decay is considered as the most promising way to prove the Majorana nature of neutrinos as well as to give an indication on the mass hierarchy and on the absolute mass scale. The discovery of 0$\nu\beta\beta$ decay would moreover open the way for theories predicting the observed matter anti-matter asymmetry of the Universe being a consequence of lepton number violation through leptogenesis.
Building upon the success of GERDA and MAJORANA experiments, the LEGEND (Large Enriched Germanium Detector for Neutrinoless $\beta\beta$ Decay) Collaboration aims at building a $^{76}$Ge-based 0$\nu\beta\beta$ experiment with a sensitivity on the half-life beyond $10^{28}$ years, to fully span the inverted neutrino mass ordering region. The LEGEND project will proceed in two steps: in the first phase, 200 kg of enriched germanium detectors are being deployed in the existing GERDA facility at LNGS. With an exposure of 1 t$\cdot$yr and a BI of 0.5 cts/(FWHM$\cdot$t$\cdot$yr), LEGEND-200 will be able to reach a sensitivity of about $10^{27}$ yr at 90$\%$ C.L. In the second phase, the enriched germanium mass will be increased up to 1000 kg. With a background index of 0.025 cts/(FWHM$\cdot$t$\cdot$yr) and with an exposure of 10 t$\cdot$yr, LEGEND-1000 will be able to reach a 3$\sigma$ half-life discovery sensitivity of 1.3$\times 10^{28}$ yr.
In this talk an overview of the LEGEND project will be presented together with the status of LEGEND-200, currently taking data at LNGS.
