Aperitivo scientifico: First Dark Matter Search Results from the XENON1T Experiment

by Marco Garbini (BO)

Friday 16 Jun 2017, 11:30 → 12:30 Europe/Rome

Aula Teorici (2 piano) (Department of Physics and Astronomy, Bologna)

We report the first dark matter search results from XENON1T, a ∼2000 kg dual-phase xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy, the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12) kg fiducial mass and in the [5, 40] keVnr energy range of interest for WIMP dark matter searches, the electronic recoil background was (1.93±0.25)×10^−4 events/(kg × day × keVee), the lowest ever achieved in a dark matter detector. A profile likelihood analysis shows that the data is consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV/c2, with a minimum of 7.7 ×10^−47 cm2 for 35-GeV/c2 WIMPs at 90% confidence level. In the full nominal 2 t × y exposure, we expect to reach with XENON1T a sensitivity of 1.6 × 10^−47 cm2. We will also present the future upgrade of the detector, XENONnT, with increased active mass and lower background, to foresee another order of magnitude improvement in sensitivity by 2023.