In a vast, dark hall, they're searching for a single person who makes almost no sound. That's how physicists hunt for sterile neutrinos — ghostly particles that pass through matter, leaving barely a trace.
A proton can't be seen as a simple ball. If you hit it with a photon, it can absorb energy and jump into an excited state, like a bell that starts ringing at a certain frequency after being struck. These states are called nucleon resonances, and they live very briefly before decaying into other particles.