New Experiments to Detect Dark Matter.

WIMP detection

The LUX-ZEPLIN (LZ) experiment, which will be built nearly a mile underground at the Sanford Underground Research Facility (SURF) in Lead, S.D., is considered one of the best bets yet to determine whether theorized dark matter particles known as WIMPs (weakly interacting massive particles) actually exist. There are other dark matter candidates, too, such as "axions" or "sterile neutrinos," which other experiments are better suited to root out or rule out.

When a theorized dark matter particle known as a WIMP collides with a xenon atom, the xenon atom emits a flash of light (gold) and electrons. The flash of light is detected at the top and bottom of the liquid xenon chamber. An electric field pushes the electrons to the top of the chamber, where they generate a second flash of light (red).  

LZ will be at least 50 times more sensitive to finding signals from dark matter particles than its predecessor, the Large Underground Xenon experiment (LUX), which was removed from SURF last year to make way for LZ. The new experiment will use 10 metric tons of ultra-purified liquid xenon, to tease out possible dark matter signals. Xenon, in its gas form, is one of the rarest elements in Earth's atmosphere.

Axion Detection

A detection device designed and built at Yale is narrowing the search for dark matter in the form of axions, a theorized subatomic particle that may make up as much as 80% of the matter in the universe.

Axion which has no charge, no spin, and a miniscule amount of mass—has all of the necessary properties to be a compelling dark matter candidate. The observed dark matter density in our galaxy requires roughly 10 trillion axions per cubic centimeter; however, their direct interactions with ordinary matter are so feeble that their detection requires extremely sensitive experimental techniques.

Axion detectors use intense magnetic fields to convert axions into detectable microwave photons at a specific frequency determined by the unknown axion mass. Previous experiments have searched for low-mass axions. Pushing the search to higher masses has been challenging for scientists because it requires high-frequency detectors that are physically smaller, and the signals from axion conversion in such cases is weaker.