QCD (Quantum Chromodynamics): the theory of the strong force. Quarks: up/down/charm/strange/top/bottom — 6 flavors, 3 colors (red/green/blue). Gluons: 8 massless gauge bosons mediating strong force, carry color charge. Color confinement: free quarks never observed — only color-neutral (white) hadrons. Hadrons: baryons (3 quarks, e.g. proton=uud), mesons (quark-antiquark). Asymptotic freedom: coupling constant decreases at high energy (Gross, Politzer, Wilczek — Nobel 2004). Running coupling:...
- physics
- qcd
- particle-physics