How do hadrons differ from all other subatomic particles?
1 Answer
They are composite particles made of quarks. Because of the nature of the strong force, quarks are never observed singly.
Explanation:
Some hadrons have two quarks (they’re called mesons meaning middle mass particles) and some have three (they’re called baryons meaning heavy particles.)
Other configurations have been proposed, notably the tetra-quark and penta-quark, and in 2015 physicists at CERN we’re delighted to announce the arrival of a new particle (https://www.nature.com/news/forsaken-pentaquark-particle-spotted-at-cern-1.17968)
Evidence for tetra-quarks is more statistically tenuous, but you can judge for yourself here: https://futurism.com/tetraquark-evidence-mounts-with-help-from-the-large-hadron-collider/
Just for completeness, hadrons are fermions (they obey the Pauli exclusion principle) but unlike leptons they respond to the strong force (and residual strong force) as well as the weak and electromagnetic forces that influence leptons. Nobody really knows how they respond to gravitational forces as the theories we have for gravity are incompatible with quantum chromodynamics (QCD).
