Abstract

Do you understand Quantum Mechanics? Well, Quantum Field Theory is even worse. Representing quantum dynamics of a system with undefined – and undefinable – number of objects, it offers many troubles of both technical and conceptual nature.

In spite of this, in turns out that many important QFT observables allow for a simple interpretation based on classical considerations. Markedly, this is the case of dynamics of quark-gluon multiplication inside QCD jets,- so-called parton evolution equations that form the ground for all modern high energy experiments at LHC and elsewhere.

We will discuss when and why classical dynamics applies to QCD phenomena.

In particular, paying due respect to the classical nature of radiation of (relatively) soft gluons helps to avoid conceptual mistakes in constructing the theory of production of heavy-quark bound states. It may also offer a breathtaking possibility to find one day a complete (all-order) analytical solution of the parton dynamics with the help of the maximally super-symmetric QFT of Yang-Mills fields (N=4 SYM ) – a close relative of QCD .