General Motivation

• The hadron spectrum: stable particles and resonances. 

• Mention: isoQCD vs QCD. Why photons make trouble. What corrections to expect.

• Recap: 2-point functions, masses/energies, amplitude.

• Overview what matrix elements will be of interest.
  Example: π → lν_l: ⟨Ω|A_μ|π(p)⟩ = i 2F_π p_μ. Matrix element from a 2-point function (1 → 0 process). Local operator, dimension, Lorentz-structure, normalization. 

• Differential cross sections at low and high momentum transfer and connection to form factors and structure functions. Inclusive vs. exclusive.

• Charges: interaction with Dark Matter at small recoil. Decoupling of heavy flavours.

• Recap: interpolators, parity, spin/helicity/chirality, quantum numbers, normalization of states, baryon spinors.

• Charges from 3-pt functions in the forward limit (1 → 1 process).