First results from GERDA Phase II

The GErmanium Detector Array (GERDA ) experiment, located at the Laboratori Nazionali del Gran Sasso, searches for the 0νββ decay of $^{76}$Ge. GERDA Phase II was started in December 2015, aiming to reach a sensitivity on the 0νββ decay half-life larger than 10$^{26}$ yr in three yr of data taking with about 100 kg·yr exposure with background index of about 10$^{−3}$ cts/(keV·kg·yr). The major upgrade of Phase II is the deployment of thirty newly produced Broad Energy Germanium detectors. They contribute to the background reduction with better energy resolution and enhanced pulse shape discrimination. To achieve the necessary background reduction, the setup was complemented with LAr veto. After 6 months of operation a first data release with 10.8 kg·yr exposure was performed, showing that the background goal has been achieved. A new lower limit on the 0νββ decay half life of Ge-76 of 5.3 · 10$^{25}$ yr (90% C.L.) has been set.