Double charmonia production in exclusive Z-boson decays

Rare Decays of the Z-Boson

We study radiative decay modes of the Z-boson into heavy quark bound states. We find that the widths for these decays are extremely small. We conclude that these decays will not be detectable for the time being unless there is a significant increase in the number of Z-bosons produced at the electronpositron colliders. Rare decays of the Z-boson have recently been studied at the ee colliders, CE...

Search for Exclusive Z-Boson Production and Observation of High-Mass pp-bar-->p gamma

Prompt Charmonium Production in Z Decays

The color-evaporation model quantitatively describes all data on photoproduction and hadroproduction of charmonium. Although the model is in part nonperturbative, the associated parameters can for instance be determined from the charmonium photoproduction data. At this point its predictions for the prompt production of ψ’s at the Z pole are made with no free parameters. We show here that this a...

Λ ( 1520 ) production in Z decays

Preliminary DELPHI results from two analyses are presented: 1. Λ(1520) production in Z0→qq, 2. Inclusive ρ, f0(980), f2(1270), K ∗0 2 (1430) and f ′ 2(1525) production in Z 0→ qq. Both analyses are based on about 2 million multihadronic events collected in 1994 and 1995, using the particle identification capabilities of the DELPHI Ring Imaging Cherenkov detectors and measured ionisation losses ...

Heavy Quark Production in Z Decays

We present studies of 3-jet nal states from hadronic Z decays recorded by the SLD experiment. A comparison of the strong couplings of light, c, and b quarks is made using 3-jet rates. We have performed a detailed study of ee ! b bg nal states, in which the quark, antiquark, and gluon jets are identi ed. The gluon energy spectrum, measured over the full kinematic range, is consistent with the pr...