1. The particle zoo
| Quarks | up | down | strange | |
|---|---|---|---|---|
| Leptons | electron | muon | electron neutino | muon neutrino |
| Gauge bosons | gluon | photon | W boson |
Hadrons
Hadrons are not fundamental particles, they are made up of quarks.
Quarks, and hence, all hadrons experience the strong force and interact via its influence
Baryons
Baryons are made up of three quarks or three anti-quarks, e.g. protons and neutrons
Mesons
A meson is a particle that is made up of a quark/anti-quark pair.
There are no stable mesons; they all have very short half lives.
A strange puzzle
Kaons are mesons that are created when protons collide at high speed (they are created via the strong force)
These mesons then decay beyond the nucleus so they must decay via the weak force.
This property was called “strange” so kaons (and the pions they decay into) are called strange particles.