Particle accelerator byproduct

MESON

This subatomic particle, first discovered in cosmic rays, often mediates the strong nuclear force and comes in varieties like pi or kaon.

A particle accelerator byproduct refers to subatomic particles created during high-energy collisions, and "meson" fits perfectly as one such particle. Mesons are unstable particles made of quark-antiquark pairs, commonly produced in accelerators like the Large Hadron Collider. The clue is straightforward—no wordplay—just a direct reference to physics terminology. If you know basic particle physics, "meson" is the obvious answer.