Y. Shimizu

In 2016, the LHCb detector at the Large Hadron Collider recorded millions of proton-proton collisions. Among the debris of these collisions, neutral B mesons were born—particles that can spontaneously transform into their antiparticles and back.

In the LHCb detector at the Large Hadron Collider, protons collide, and for a fleeting moment, particles that don't exist in ordinary matter are born. One of them is the neutral B meson. It lives for less than a billionth of a second and decays into two other particles: the narrow resonance J/ψ and the broader ρ(770).

In a giant particle accelerator, where protons traveling at nearly the speed of light smash into a neon target, charmed baryons are born — particles that live for less than a billionth of a second.

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.

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 high-speed collision knocked a neutron out of a helium-8 nucleus, and for an instant a helium-7 nucleus appeared, like an overloaded shelf shedding three books at once. This fleeting 'sound' of decay was captured for the first time: three neutrons flew apart, leaving behind an ordinary helium-4 nucleus.

Two tin nuclei collide at about two-thirds the speed of light. For an instant, a hot, dense cloud forms, and protons fly out in all directions. If you catch pairs of protons and measure how often they fly off in the same direction, you can work out the size of that cloud. This method is called femtoscopy: it works like a microscope for nuclear scales.

A coin landing on its edge is about as rare as a heavy B meson decaying into a light pion and an electron-positron pair. Over a decade of collider operation, only a handful of such events have accumulated, but physicists have finally managed to spot them. The decay probability is about 2.4×10⁻⁸.