WIMPING OUT The XENON1T experiment (contained inside the large tank above, at left) reports no hint of any interactions from particles of dark matter within, despite a yearlong search.
Roberto Corrieri and Patrick De Perio
The largest particle detector of its kind has failed to turn up any hints of dark matter, despite searching for about a year.
Known as XENON1T, the experiment is designed to detect elusive dark matter particles, which are thought to make up most of the matter in the cosmos. Physicists don’t know what dark matter is. One of the most popular explanations is a particle called a WIMP, short for weakly interacting massive particle. XENON1T searches for WIMPs crashing into atomic nuclei in 1,300 kilograms of chilled liquid xenon. But XENON1T saw no such collisions. The particles’ absence further winnowed down their possible hiding places by placing new limits on how frequently WIMPs can interact with nuclei depending on their mass.
Researchers describe the results May 28 in two talks, one at Gran Sasso National Laboratory in Italy, where XENON1T is located, and the other at the European particle physics lab CERN in Geneva. XENON1T had previously reported no hint of WIMPs using about a month’s worth of data (SN: 9/30/17, p. 17). The new study, however, was highly anticipated by physicists, as the longer search provided a better chance for spotting WIMPs.
As the WIMP window narrows, scientists are preparing to rev up the search, creating larger, more sensitive WIMP detectors, and moving on to search for other possible dark matter particles, such as axions (SN Online: 4/9/18).