A new-generation dark matter detector has started operations, already delivering its first results, which show that it is the most sensitive machine of its type on Earth.
The machine could help unravel one of physics’ greatest mysteries – the nature of black matter— by directly detecting its constituent particles for the first time.
Located deep beneath the Black Hills of South Dakota, the LUX-ZEPLIN (LZ) experiment – led by a team of 250 scientists led by Lawrence Berkeley National Lab (Berkeley Lab) – has passed the verification phase of its start-up procedure with flight colors.
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The LZ detector has been operational since December 2021, and these initial results represent its first 60 days of live operation. “We’re ready and all is well,” said Kevin Lesko, Berkeley Lab senior physicist and former LZ spokesperson. statement (opens in a new tab). “It’s a complex detector with many parts and they all work well within expectations.”
Dark matter makes up about 85% of the matter in the known world. universe , but because it does not interact with light, it is virtually invisible. Similarly, whatever particles make up dark matter, they also do not interact strongly with other matter.
In fact, the only way scientists can infer the presence of dark matter is through its gravitational influence which literally holds most galaxies together, preventing their constituent stars from separating as they rotate.
This means researchers know that dark matter is not made up of protons and neutrons like the everyday matter – or baryonic matter – we see around us every day.
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The LUX-ZEPLIN detector is configured to specifically search for a hypothetical type of dark matter called massive, weakly interacting particles,or WIMPs. These particles are expected to very rarely collide with matter and to interact extremely weakly when they do.
No dark matter particles have currently been directly detected, but the hope is that the LZ detector can change that by detecting the weak interactions of these mysterious particles with xenon atoms. This requires a sensitive detector with all possible noise that could interfere with detection eliminated.
The xenon for the LZ experiment is in two nested titanium tanks containing ten tons of the element in a liquid state. These reservoirs are monitored by two photomultiplier tube (PMT) arrays that are ready to detect weak light sources.
The tanks and their associated detectors are also within a larger detection system that can catch any particles that might mimic the dark matter signal and eliminate it from the hunt for true dark matter.
To spot these weak interactions, xenon tanks must be maintained at minus 148 degrees Fahrenheit (minus 100 degrees Celsius). Additionally, the LZ team must remove all natural background radiation from the detector. A water reservoir surrounds the experiment with natural radiation emitted by radiation from the walls of the laboratory.
The Dark Matter Detector’s underground location helps shield it from high-energy protons and atomic nuclei that travel through space at nearly the speed of light and originate from the Sun and beyond the Solar System called cosmic rays. .
The sensitivity of the LZ detector will be further enhanced over the next 1000 days, which means that this is just the beginning of the experiment.
“We expect to collect about 20 times more data in the coming years, so we’re just getting started,” University of California Santa Barbara LZ spokesperson Hugh Lippincott said in a statement. statement (opens in a new tab). “There’s a lot of science to do and it’s very exciting!”
The first results from the detector have been published on the site (opens in a new tab) LZ experiments Thursday July 7th.
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