Dark matter detector reaches record sensitivity with new calibration methods
The XENONnT experiment has achieved the lowest background noise ever recorded in a dark matter detector, opening a new window to observe rare physics events. The breakthrough could accelerate the discovery of dark matter particles—a finding worth billions in scientific prestige and potentially transformative for physics beyond current understanding.
Originaltitel: XENONnT analysis: Signal reconstruction, calibration, and event selection
<p>The XENONnT experiment, located at the INFN Laboratori Nazionali del Gran Sasso, Italy, features a 5.9 tonne liquid xenon time projection chamber surrounded by an instrumented neutron veto, all of which is housed within a muon veto water tank. Because of extensive shielding and advanced purification to mitigate natural radioactivity, an exceptionally low background level of (15.8±1.3) events/(tonne·year·keV) in the (1,30) keV region is reached in the inner part of the time projection chamber. XENONnT is, thus, sensitive to a wide range of rare phenomena related to dark matter and neutrino interactions, both within and beyond the Standard Model of particle physics, with a focus on the direct detection of dark matter in the form of weakly interacting massive particles. From May 2021 to December 2021, XENONnT accumulated data in rare-event search mode with a total exposure of one tonne·year. This paper provides a detailed description of the signal reconstruction methods, event selection procedure, and detector response calibration, as well as an overview of the detector performance in this time frame. This work establishes the foundational framework for the “blind analysis” methodology we are using when reporting XENONnT physics results.</p>