2019 Impact factor 4.389
Particles and Fields
Eur. Phys. J. C 32, 253-260 (2004)
DOI: 10.1140/epjc/s2003-01369-y

CP violation in the 3 jet and 4 jet decays of the Z boson at GigaZ

O. Nachtmann1 and C. Schwanenberger2

1  Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
2  Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22603 Hamburg, Germany

O.Nachtmann@thphys.uni-heidelberg.de
schwanen@mail.desy.de

(Received: 21 August 2003 / / Published online: 20 November 2003)

Abstract
We review CP-violating effects in $Z \rightarrow 3$ jet and $Z \rightarrow$ 4 jet decays, assuming the presence of CP-violating effective $Z b \bar{b} G$ and $Z b \bar{b} G G$ couplings. Longitudinal beam polarization is included in the studies. We propose a direct search for such CP-violating couplings by using various CP-odd observables. The data of a future linear collider running at the Z-resonance in the so-called GigaZ option should give significant information on the couplings. Finally we show that stringent bounds on the mass of excited b quarks can be derived if appropriate couplings are of a size characteristic of a strong interaction.



© Società Italiana di Fisica, Springer-Verlag 2004