This course is taught at two years interval in the Autumn semester of even years and follows up on the introductory course on particle physics that is given yearly in the Spring semester. The framework in which particle physics is formulated and understood is introduced and the basic concepts that allow to understand particles and their interactions from first principles are discussed.

**Part VII – Particles and interactions**

Cross sections

Fermi’s golden rule

Interaction cross section

Interaction by particle exchange

Feynman diagrams

Yukawa potential

Discovery of the pion

**Part VIII – Particles and antiparticles**

The Dirac equation

Antiparticles

Discovery of the positron

Spin and helicity

Chirality

Pion decay

**Part IX – Physics at lepton colliders**

Fermion-fermion scattering

Feynman rules

Positron-electron colliders

The e

^{+}e

^{-}→ 𝜇

^{+}𝜇

^{-}cross section

Discovery of the tau lepton Muon and tau decays

Hadronic R–ratio

Discovery of the gluon

Resonances

Discovery of the gluon

Resonances

**Part X – Hadrons: Mesons and Baryons**

Mesons as bound qq̅–states

Symmetries and conservation laws

**Part XI – The Standard Model**

Symmetries at the base of the Standard Model

U(1) → Quantum Electrodynamics — QED

U(1)

_{Y}× SU(2)

_{L}→ Electroweak unification

SU(3)

_{C}→ Quantum Chromodynamics — QCD

The Brout–Englert–Higgs Mechanism

The End and open questions

- Teacher: Hans Peter Beck