EPJ

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EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 7, 487-499
DOI 10.1007/s100529801011

The rare K-decays in the Multiscale Walking Technicolor Model

Z.J.Xiao1,2 - L.X.Lü2 - H.K.Guo2 - G.R.Lu1,2

1 CCAST(World Laboratory) P.O. Box 8730, Beijing 100080, P.R. China
2 Department of Physics, Henan Normal University, Xinxiang, 453002 P.R. China

Received: 17 June 1998 / Revised version: 12 August 1998 / Published online: 6 November 1998

Abstract
We calculate the one-loop Z0-penguin contributions to the rare K-decays, $K^+ \to \pi^+ \nu \bar \nu$,$K_L \to \pi^0 \nu \bar \nu$ and $K_L \to \mu^+ \mu^-$,from the unit-charged technipions $\pi_1$ and $\pi_8$ in the framework of the Multiscale Walking Technicolor Model. We find that: (a) the $\pi_1$ and $\pi_8$ can provide one to two orders enhancements to the branching ratios of the rare K-decays; (b) by comparing the experimental data of $Br(K^+ \to \pi^+ \nu \bar \nu)$ with the theoretical prediction one finds the lower mass bounds, $m_{p8} \geq 249\,{\rm GeV}$ for $F_Q=40\,{\rm GeV}$ and $m_{p1}=100\,{\rm GeV}$;(c) by comparing the experimental data of $Br(K_L \to \mu^+ \mu^-)$with the theoretical predictions one finds the lower bounds on mp1 and mp8, $m_{p1} \geq 210\,{\rm GeV}$ if only the contribution from $\pi_1$ is taken into account, and $m_{p8} \geq 580\,{\rm GeV}$ for $m_{p1}=210\,{\rm GeV}$, assuming $F_Q=40\,{\rm GeV}$;(d) the assumed ranges of the masses mp1 and mp8 in the Multiscale Walking Technicolor Model are excluded by the rare K-decay data.

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