BESIII Collaboration

Among the debris of particle collisions, short-lived 'guests' sometimes appear — hyperons. One of them, Σ0, lives for less than one ten-billionth of a second and decays on the fly. Catching it directly is nearly impossible, but its traces can be spotted: it leaves behind another particle, Λ, and an electron-positron pair.

An archaeologist carefully brushes away layer after layer, and each new stratum at the charmonium dig is a rare decay captured by the detector. Charmonium — a bound state of a charm quark and its antiquark — lives for mere fractions of a second, yet it manages to tell us about the forces that hold quarks together.