Study · Topic 2
QCD essentials — asymptotic freedom, factorization, DGLAP
The three theorems that turn the parton picture into a precision science. Each section below is a full chapter: complete mathematical treatment, derivations, diagrams, and worked examples.
2.1Colour, the Lagrangian, and the running couplingThe β-function, asymptotic freedom, Λ_QCD — with the one-loop running solved.
2.2Factorization and coefficient functionsThe theorem, MS̄ scheme, higher twist — why PDFs are universal and where that fails.
2.3DGLAP: derivation and splitting functionsP_qq derived at LO, plus-distributions, the full LO kernel set, moments.
2.4Evolution in practiceMellin solutions, small-x growth, heavy-flavour schemes, and the EKO/FK pipeline.