Eur. Phys. J. C 16, 269-278
DOI 10.1007/s100520000424
Probe of the Wtb coupling in 
pair production
at linear colliders
E. Boos1,2 - M. Dubinin1,2 - M. Sachwitz2 - H.J. Schreiber2
1 Institute of Nuclear Physics, Moscow State University,
119899, Moscow, Russia
2 DESY-Zeuthen, 15738 Zeuthen, Germany
Received: 20 January 2000 / Revised version: 12 April 2000
/
Published online: 18 May 2000 - © Springer-Verlag 2000
Abstract
The Wtb vertex can be probed on future
colliders in the processes of single top
production (LHC, pp mode, NLC, 
mode)
and of top pair production (NLC, e+ e- mode).
We analyze observables sensitive to anomalous Wtb couplings in the top pair production process of e+ e- collisions.
In particular, forward-backward and spin-spin asymmetries
of the top decay products and the asymmetry
of the lepton energy spectrum are considered.
Possible bounds on anomalous couplings obtained
are competitive
to those expected from the upgraded Tevatron and LHC.
The validity of the infinitely small width
approximation for the three-body top decay is also studied in
detail.
Copyright Società Italiana di Fisica, Springer-Verlag 2000
