Visualisation of the interaction observed between a proton (left) and a phi meson (right) as they emerged from a proton-proton collision at the Large Hadron Collider (LHC) at CERN (European Particle Physics Laboratory) in 2021. The proton has two up and a down quark (yellow), while the phi meson has strange-antistrange quarks (red). Since the phi meson is not electrically charged, the interaction between the proton and the phi can only be attributed to the residual strong interaction. The LHC collisions produce hadrons very close to each other at femtometre distances, which matches the range of the residual strong force. This gives the hadrons a brief opportunity to interact before flying away. Understanding the strong force that governs the behaviour of quarks helps scientists understand how particles bind together at a fundamental level.