When analyzing data from the XENON1T detector for dark matter, a signal excess was observed. The UZH researchers do not yet know for sure where this unexpected signal comes from. They say the origins could be relatively banal, but they could also indicate the existence of new particles or hitherto unknown properties of neutrinos.
Since the end of 2018, the XENON1T detector in the underground laboratory at Gran Sasso, part of the National Institute for Nuclear Physics in Italy, has been searching for particles of dark matter, the material that makes up 85 percent of the matter in the universe. The world’s most sensitive detector has not yet found any particles of dark matter, but some unusual events have been observed. If a particle flies through the liquefied xenon, it may collide with the xenon atoms, thereby triggering weak light signals and hitting electrons from the affected xenon atom. When comparing the XENON1T data with the expected 232 events of known particles, however, the researchers found a surprising excess of 53 events.