What are hadrons?
Sounds like more of particle physics. Hadrons are made of quarks. Protons and neutrons are most common examples of hadrons which were earlier thought of as fundamental/elementary/indivisible particles (in fact sometimes even atom was thought of as fundamental/elementary/indivisible particle in the past) but that view has changed. Hadrons can be broken up into smaller fundamental/indivisible particles. Smashing hadrons into smaller particles are activities done at colliders like LHC.