Hosted by: Hanyu Wei

Abstract: For more than a decade, the XENON Collaboration has been designing and operating a family of liquid xenon-filled detectors with the aim of catching dark matter Weakly Interacting Massive Particles (WIMPs). Although the road to discovery did not come to an end yet, the successive XENON detectors always placed the most stringent limits to the WIMP mass and interaction cross section with ordinary matter, in particular thanks to their highly controlled radioactive environment. Taking advantage of years of thorough R&D in the subject, the latest of our running experiments, XENON1T, proved to be the most sensitive detector for WIMP direct search to date. Despite being first optimised for the observation of WIMP-induced xenon nuclear recoils, the unprecedented low electronic background of 76 events per (tonne × year × keV) in the 1–30 keV range achieved by the XENON1T experiment made it sensitive to phenomena manifested by low-energy electron recoils. Recently, the XENON Collaboration reported an excess of such events which has been interpreted as a possible evidence of new physics (solar axions, a neutrino magnetic moment or bosonic dark matter) or by the presence of unexplored background sources so far (tritium and argon). After an introduction to dark matter direct detection with XENON1T and a review of its main contributions to the field, this result will be discussed in detail, from the analysis to interpretations of the observed excess.