DOI 10.1007/s100529900048
The rare K decays and Z0 penguin contributions in the topcolor-assisted technicolor models
Zhenjun Xiao1,2,3 - Chongsheng Li1,2 - Kuangta Chao1,2
1 CCAST (World Laboratory), P.O. Box 8730, Beijing 100080,
P.R. China
2 Department of Physics, Peking University,
Beijing 100871, P.R. China
3 Department of Physics, Henan Normal University,
Xinxiang 453002, P.R. China
Received: 24 November 1998 / Revised version: 16 February 1999 /
Published online: 15 July 1999
Abstract
We calculate the new contributions to the rare decays K,
and
from new Z0 penguin and box diagrams induced by
the unit-charged scalars
appearing in the
topcolor-assisted technicolor (TC2) models. We find that:
(a) the unit-charged top-pion
and b-pion
can provide large contributions to the rare K decays
if they are relatively light;
(b) the size of the mixing elements
(
) is strongly
constrained by the data of B0 meson mixing:
for
and
GeV;
(c) the enhancements to the branching ratios of rare K decays
from new scalars can be as large as one order of magnitude;
(d) there is a strong cancellation between the short- and
the long-distance dispersive part of
the decay
, the constraint on the new short-distance
part from this decay mode is thus not strong;
(e) the typical TC2 model under study is generally consistent with the
available rare K-decay data.
Copyright Springer-Verlag