Editorial

The production of charmed mesons ,D ^± , andD ^*± is studied in a sample of 478,000 hadronicZ decays. The production rates are measured to be

A measurement of the η radiative width Γη→γγ

The radiative width of the η meson has been measured at PETRA in photon-photon collisions. The resulting value is Γ_η→γγ = 0.53±0.04±0.04 keV.     

Observation of a charge asymmetry in e+e− → μ+μ−

The angular distribution and the s dependence of the total cross section for the process e⁺e^? → μ⁺μ^? have been measured using the JADE detector at PETRA. After radiative corrections, a forward-backward asymmetry of ?(11.8±3.8) % was observed at an average centre of mass energy of 33.5 GeV. For comparison, an asymmetry of ?7.8 % is expected on the basis of the standard Glashow-Salam-Weinberg model.     

Prompt muons in multiparticle events from e+e− annihilation at petra

We have observed the production of prompt muons in e⁺e^? annihilation in the centre of mass energy range 33.0 GeV to 35.8 GeV. The rate of such muons with momentum greater than 1.4 GeV was measured to be 0.069 ± 0.024 per multiparticle event. When compared with currently accepted models, this rate is consistent with that expected from charm and bottom decays, but does not support the production also of a top quark of mass less than about 15 GeV.     

New Section in EPJ C direct: Young Scientists

This section is part of EPJ C direct and is dedicated to outstanding contributions from young scientists. The section is launched with the prize winners of the International School of Subnuclear Physics held at Erice in summer 2003 and organized by A. Zichichi and G. t Hooft. The participants of the School had the opportunity to present their own scientific work in the Special Sessions for New Talents in front of a critical audience. A jury of the organizers, the lecturers and invited distinguished scientists selected the most prominent contributions and invited the authors to submit their work. Heidelberg, October 2004Published online: 3 November 2004Jochen Bartels, Dieter Haidt: Editors-in-ChiefThis revised version was published online in November 2004 with changes to the abstract.