Berkeley Lab in race to create first successful dark matter detector

Lawrence Berkeley National Laboratory/Courtesy

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Researchers at the Lawrence Berkeley National Laboratory are trying to create the first experiment to successfully detect dark matter.

The experiment, known as the LUX-ZEPLIN, or LZ experiment, is designed to directly detect dark matter — specifically weakly interacting massive particles, or WIMPs. The researchers expect to operate the experiment by 2020 and will receive their first set of data in 2021.

“There’s only a handful of experiment results that you can imagine that would have the impact that an observation of dark matter would have,” said Carter Hall, spokesperson for the LZ experiment. “It would basically revise everything we know about particle physics.”

The LZ experiment involves the construction of a chamber of liquid xenon, which increases the likelihood of direct interaction with a WIMP. According to Hall, the chamber will allow researchers to observe dark matter particles bouncing off the xenon nuclei, similar to the effect of billiard balls.

The experiment will be constructed a mile underground at the Sanford Underground Research Facility in Lead, South Dakota in order to shield it from cosmic rays, according to Murdock “Gil” Gilchriese, LZ project director and Berkeley lab physicist. Gilchriese added that being underground will ensure low radioactivity.

The LZ experiment will replace the previous Large Underground Xenon experiment, or LUX, which also aimed to detect dark matter and included many of the same members of LZ. LUX only used 370 grams of the rare liquid xenon as opposed to the ten tons being used in LZ, which will make the chamber 50 times more likely to detect dark matter.

The LZ project is racing against similar experiments in Italy and China, which, according to LZ researchers, will benefit the project, allowing them to verify the results of their research.

“If one of these experiments had in their data what they thought was a genuine signal for dark matter … (the other) experiments can then check, and can attempt to do the same measurement and can either confirm or not confirm the results of such a detection,” Hall said.

Kathryn Zurek, a dark matter theorist and physicist at Berkeley lab, said if WIMPs are found during the course of the experiment, it will be one of the biggest discoveries in physics.

“It is a little hard to overstate its significance,” Zurek said, adding that it will open up an “entirely new area of research.”

Even if the experiment were to yield a negative result, detecting no WIMPs, Zurek said she believes the experiment will still be considered a success.

“It’s about finding where the dark matter is not, so we can push in new directions,” Zurek said. “If the result is negative, it will direct more of the communities’ efforts in other directions.”

Contact Kate Tinney and Sydney Fix at [email protected].

A headline accompanying a previous version of this article may have implied that the Berkeley Lab researchers aim to create the first dark matter detector. In fact, they aim to create the first successful one.