H. H. Liu

In the accelerator, an electron and a positron collide, and for an instant, a particle is born that lives for less than a billionth of a second. Its decay resembles the explosion of a tiny firecracker: fragments scatter in all directions, and physicists reconstruct what was inside from their trajectories.

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.