Proton collisions at the Large Hadron Collider produce particles that live for less than a billionth of a second. One of them is the Bs meson, made of a strange quark and a bottom antiquark.
A tiny ghostly particle zips through a piece of germanium. Usually it leaves no trace, but sometimes, like a billiard ball, it smacks into an atom's nucleus. The nucleus recoils, and that jolt can be detected. At Oak Ridge National Laboratory, the Ge-Mini detector caught such recoils for two years.
Neutrinos are the most elusive of known particles.