https://phys.org/news/2018-05-xenon1t-experimental-stringent-limit-dark.html

"We now have the tightest limit for what is known as 'the WIMP-nucleon cross section,' which is a measure of the effective size of dark matter, or how strongly it interacts with normal matter," said Ethan Brown, a member of the XENON Collaboration, and assistant professor of physics, applied physics, and astronomy at Rensselaer Polytechnic Institute. "With these results, we have now tested many new theoretical models of dark matter and placed the strongest constraints on these models to date."

Dark matter is theorized as one of the basic constituents of the universe, five times more abundant than ordinary matter. But because the dark matter particles known as "weakly interacting massive particles," or "WIMPs," cannot be seen and seldom interact with ordinary matter, their existence has never been confirmed.