1. Fundamental principles of particle physics
G.Ross, CERN, July08

2. Fundamental principles of particle physics
G.Ross, CERN, July07
Outline
Introduction - Fundamental particles and interactions
Symmetries I - Relativity
Quantum field theory - Quantum Mechanics + relativity
Theory confronts experiment - Cross sections and decay rates
Symmetries II – Gauge symmetries, the Standard Model
Fermions and the weak interactions

3. Fundamental principles of particle physics
G.Ross, CERN, July07
Fundamental Interactions

4. Fundamental Interactions
Fundamental principles of particle physics
G.Ross, CERN, July07
Fundamental Particles
Fundamental Interactions

5. Fundamental Interactions
Fundamental principles of particle physics
G.Ross, CERN, July07
Fundamental Particles
Fundamental Interactions
Strength
Size

6. r E

7. Choose units such that :
Length : L
Time : T
Energy : E
or Mass : m
Natural Units
Choose units such that :
1 unit left : choose

8. Natural Units
Dimensionless-
same in any units

9. Fundamental Interactions and sizes
Atomic binding :
Nuclear binding :

10. Elementary particles Leptons : Quarks :
Isador Rabi 1937 “Who ordered the muon?”
Elementary particles
Leptons :
Quarks :

11. Elementary particles Leptons : Quarks : Hadrons :
3 strong “colour” charges

12. Elementary forces

13. Experiments conducted in momentum space :
Feynman diagram
Exchange forces
Electromagnetism
The strength
of the force
Experiments conducted in momentum space :
Photon “propagator”

14. Experiments conducted in momentum space :
Exchange forces
Electromagnetism
Experiments conducted in momentum space :

15. Application to a scattering processes
Feynman diagram

17. Exchange forces
Strong interactions g
(Q2)
In momentum space :

18. Exchange forces Z (Q2) In momentum space : Weak force
Yukawa interaction
In momentum space :

19. Exchange forces
Gravitational force G
(Q2)

20. Exchange forces
Gravitational force G
(Q2)

23. References useful for future lectures:
Halzen & Martin, ‘Quarks & leptons’, Wiley, 1984
Aitchison & Hey, ‘Gauge Theories in Particle Physics’, Taylor and Francis, 2005
[Peskin & Schroeder, ‘Quantum Field Theory’, Addison-Wesley, 1995]