Introduction to color in QCD: Initiation to the birdtrack pictorial technique

英文摘要：

These lectures are an elementary introduction to the "birdtrack" color pictorial technique, a useful tool in QCD. We review the basic rules, discuss color conservation and infinitesimal color rotations, learn how to project on partonic color states, how to derive their Casimir charges... and at the same time learn a little bit of representation theory.