Starship Asterisk*

Berkeley Lab and UC Berkeley scientists are already pursuing new experiments to probe for low-mass dark matter particles

The search for dark matter is expanding. And going small.

While dark matter abounds in the universe – it is by far the most common form of matter, making up about 85 percent of the universe’s total – it also hides in plain sight. We don’t yet know what it’s made of, though we can witness its gravitational pull on known matter.

Theorized weakly interacting massive particles, or WIMPs, have been among the cast of likely suspects comprising dark matter, but they haven’t yet shown up where scientists had expected them.

So scientists are now redoubling their efforts by designing new and nimble experiments that can look for dark matter in previously unexplored ranges of particle mass and energy, and using previously untested methods. The new approach, rather than relying on a few large experiments’ “nets” to try to snare one type of dark matter, is akin to casting many smaller nets with much finer mesh.

Dark matter could be much “lighter,” or lower in mass and slighter in energy, than previously thought. It could be composed of theoretical, wavelike ultralight particles known as axions. It could be populated by a wild kingdom filled with many species of as-yet-undiscovered particles. And it may not be composed of particles at all. ...