Largest WIMP survey sets new limits

XENON1T data

On 28 May, the world’s largest and most sensitive detector for direct searches of dark matter in the form of weakly interacting massive particles (WIMPs) released its latest results. XENON1T, a 3D-imaging liquid-xenon time projection chamber located at Gran Sasso National Laboratory in Italy, reported its first results last year (CERN Courier July/August 2017 p10). Now, the 165-strong international collaboration has presented the results from an unprecedentedly large exposure of approximately one tonne × year.

The results are based on 1300 kg out of the total 2000 kg active xenon target and 279 days of data-taking, improving the sensitivity by almost four orders of magnitude compared to XENON10 (the first detector of the XENON dark-matter project, which has been hosted at Gran Sasso since 2005). The data are consistent with background expectations, and place the most stringent limit yet on spin-independent interactions of WIMPs with ordinary matter for a WIMP mass higher than 6 GeV/c².

XENON1T spokesperson Elena Aprile of Columbia University in the US describes the result as a milestone in dark-matter exploration. “Showing the result after a one tonne × year exposure was important in a field that moves fast,” she explains. “It is also clear from the new result that we will win faster with a yet-larger mass and lower radon background, which is why we are now pushing the XENONnT upgrade.”

Further reading

E Aprile et al. 2018 arXiv:1805.12562.