arXiv subjects
Publications and source records attributed to Klaus Hamacher.
Experimental results on event shapes obtained within (or related to) the method of Effective Charges are discussed in view of measurements of the strong coupling, alpha_s, the beta-function and non-perturbative contributions to event shapes. The data strongly advocate to use of the ECH scheme instead of the conventional MSbar scheme.
A summary of QCD results obtained at e+e- experiments in recent years is given. Emphasis is put on basic QCD tests and α_s measurements with event shapes.
Recent developments and results on the comparison of gluon to quark jets are discussed. A most important topic is the introduction of explicit energy scales of the jets. The scaling violation of the fragmentation function and the increase of the multiplicity with scale is shown to be directly proportional to the corresponding gluon or quark colour factor. The ratio of the hadron multiplicity in gluon to quark jets is understood to be smaller than the colour factor ratio due to differences in the fragmentation of the leading quark or gluon. Novel algorithms to reconstruct the colour portraits or the colour flow of an event are presented.