DOI 10.1007/s100520000511
Leptoquark signal from global analysis
A.F. Zarnecki
Institute of Experimental Physics, Warsaw University,
Hoza 69, 00-681 Warszawa, Poland (e-mail: zarnecki@fuw.edu.pl)
Received: 21 June 2000 / Revised version: 31 August 2000 /
Published online:
23 October 2000
- © Springer-Verlag 2000
Abstract
Data from HERA, LEP and the Tevatron as well as from low energy
experiments are used to constrain the Yukawa couplings
for scalar and vector leptoquarks
in the Buchmüller-Rückl-Wyler effective model.
In the limit of very high leptoquark masses constraints on the
coupling
to the mass ratio
are derived using
the contact-interaction approximation.
For finite masses the coupling limits are studied
as a function of the leptoquark mass.
Some leptoquark models are found to describe the existing experimental
data
much better than the standard model.
The increase in the global probability observed for models including
S1 or
leptoquark production/exchange
corresponds to an effect of more than 
.
Assuming that a real leptoquark signal is observed,
the allowed region in the 
-M plane is calculated.
The leptoquark signal mostly results from the new data
on the atomic parity violation in cesium,
but is also supported by recent LEP2 measurements,
unitarity violation in the CKM matrix
and HERA high-Q2 results.
Copyright Società Italiana di Fisica, Springer-Verlag 2000
