The next-generation dark matter detector has begun operations and is already producing its first results, showing that it is the most sensitive machine on Earth.
The machine could help unravel one of physics’ greatest mysteries — the Nature of dark matter — by directly detecting its particles for the first time.
Located deep below the Black Hills of South Dakota — operated by a team of 250 scientists led by Lawrence Berkeley National Lab (Berkeley Lab) — the LUX-ZEPLIN experiment (L.Z.) has passed the control phase of its launch procedure with flying colors.
The L.Z. detector has been in operation since December 2021, and these first results represent its first 60 days of sharp operation. “We’re ready and everything looks good,” Berkeley Lab senior physicist and former L.Z. spokesperson Kevin Lesko said in a statement (opens in new tab). “It’s a complex detector with many components, and they all work well as expected.”
Dark matter makes up about 85% of the matter in the known universe, but because it does not interact with light, it is virtually invisible. Similarly, whatever the fundamental particles of dark matter are, they do not interact strongly with other matter.
In fact, scientists can only infer the presence of dark matter through its gravitational influence, which holds most galaxies together and prevents their stars from blowing apart as they spin.
Scientists know that dark matter is not made up of protons and neutrons like the everyday matter — or baryonic matter — we see around us daily.
The LUX-ZEPLIN detector is set to look for a hypothetical type of dark matter called weakly interacting massive particles, or WIMPs. These particles are expected to collide with matter very rarely; when they do, they interact exceptionally weakly.
Currently, no dark matter particles have been directly detected. Still, we hope that the L.Z. detector could change that by seeing the weak interactions of these mysterious particles with xenon atoms. This requires a sensitive sensor with the elimination of all possible noise that could interfere with detection.
The xenon of the L.Z. experiment is in two embedded titanium tanks containing ten tons of the element in a liquid state. These tanks are monitored by two photomultiplier arrays (PMTs) ready to detect weak light sources.