LUX-ZEPLIN Experiment Narrows Down Potential Hiding Places for Dark Matter
In a significant leap forward for cosmology, scientists have made remarkable progress in the search for dark matter, a mysterious substance that has eluded direct detection for decades. The LUX-ZEPLIN (LZ) experiment, one of the world’s most sensitive dark matter detectors, has substantially narrowed the range of possible properties for dark matter particles, researchers announced on August 26 at two prominent conferences.
Dark matter is an enigmatic substance that exerts a gravitational pull on galaxies and galaxy clusters, influencing their behavior in ways that cannot be explained by ordinary matter alone. Despite its profound impact on the cosmos, dark matter has never been directly observed. This makes the quest to identify its nature one of the most pressing challenges in modern physics.
The LZ experiment focuses on detecting a specific type of dark matter particle known as a weakly interacting massive particle, or WIMP. These hypothetical particles are thought to interact with normal matter through gravity and possibly the weak nuclear force, but they have evaded detection due to their extremely weak interactions with ordinary matter. The LZ experiment is particularly sensitive to WIMPs with masses exceeding 9 billion electron volts—about nine times the mass of a proton.
The LZ detector, located deep underground to shield it from cosmic rays and other interference, is filled with 10 metric tons of liquid xenon. This noble gas serves as a target for WIMPs, which, if they exist, would occasionally collide with the xenon nuclei, causing them to recoil. By monitoring these recoil events, scientists can search for signs of dark matter.
In their latest analysis, the LZ researchers have made substantial progress by reducing the maximum possible cross section—the likelihood that a WIMP will interact with the xenon atoms. The new findings shrink this cross section to about one-fifth of the limit set by previous experiments, effectively eliminating a significant portion of the parameter space where WIMPs could be hiding.
“We are making massive strides into new territory,” says physicist Chamkaur Ghag of University College London, who serves as the spokesperson for the LZ experiment. “This is a critical step in our quest to unravel the mystery of dark matter.”
The study, which analyzed 280 days’ worth of data, represents a significant milestone in the search for dark matter. However, the LZ experiment is far from finished. The final results, expected after 1,000 days of data collection, will provide an even more comprehensive picture, potentially carving away more of the dark matter’s possible characteristics or, if fortunate, revealing the first direct evidence of dark matter particles.
As the scientific community eagerly awaits the final results, the LZ experiment continues to push the boundaries of our understanding of the universe, bringing us ever closer to solving one of the greatest mysteries in physics.
