M. Wada

A bullet that doesn't just pierce one target but leaves marks in several layers of armor. That's roughly how superheavy dark matter behaves, and it's what the DarkSide-50 detector was built to catch for the first time. The usual suspects for dark matter (weakly interacting massive particles, or WIMPs) pass through matter almost unnoticed, occasionally bumping into a nucleus.

In the dark chamber of the detector, argon waits. When an invisible particle (say, a dark matter candidate) flies through, it gives the argon nucleus a gentle shove. The nucleus is knocked out of place, and charges are born around it. Exactly how many charges is no trivial question: physicists use that number to tell what kind of visitor dropped by.

When matter accumulates on the surface of a neutron star, the ultra-dense remnant of a dead star, an explosion occurs, akin to a giant thermonuclear bomb. In this inferno, nuclei of elements not found on Earth are born within seconds. To understand which ones, their masses must be known with great precision.