Jet physics at LEP and QCD

by Igor DREMIN (Lebedev Physical Institute, Moscow)

Friday 21 Mar 2003, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

The theory of strong interactions, quantum chromodynamics (QCD), is quite successful in predicting and describing many features of multiparticle production processes at high energies. In this talk, the general perturbative QCD approach to these processes (primarily, to jets in e⁺e^--annihilation) is briefly formulated, and associated problems are discussed. It is shown that analytical calculations at the parton level with the help of equations for generating functionals using a low-momentum cutoff are surprisingly adequate in describing experimental data on the final hadronic state in multiparticle production processes at high energies - even though the perturbative expansion parameter is not very small. The role of higher order terms and their observation in experimental results on quark and gluon jets is discussed. It is stressed that the perturbative QCD not only describes existing data but also predicts many qualitatively new and intriguing phenomena.