Parton fragmentation and string dynamics

Аннотация

The quark-parton model is still at the basis of most of our attempts to describe hadronic phenomena. It is surprising that a model with essentially noninteracting parts describes so many properties which are not so easy to address in terms of the entities, i.e. the hadrons themselves. There is a simple and beautiful explanation by the notion of asymptotic freedom [1] for nonabelian gauge theories, in particular for quantum chromodynamics (QCD). It does, however, imply that the space-time scale where theory dwells is rather different from the one where the experimental detector setups are working. Thus while perturbative QCD-calculations can be trusted on the scale of maybe fractions of a fermi, the outcome of the hard processes are measured very far away, indeed.