TC2 Models Research Articles

Limitations of B-meson mixing bounds on technicolor theories

Recent work by Burdman, Lane, and Rador has shown that B-meson mixing places stringent lower bounds on the masses of topgluons and Z' bosons in classic topcolor-assisted technicolor (TC2) models. This paper finds analogous limits on the Z' bosons of flavor-universal TC2 and non-commuting extended technicolor models, and compares the limits with those from precision electroweak measurements. A discussion of the flavor structure of these models (contrasted with that of classic TC2) shows that B-meson mixing is a less reliable probe of these models than of classic TC2.

The process e+e−→t̄c in topcolor-assisted technicolor models

We consider the flavor changing neutral current(FCNC) process $e^{+}e^{-}\to\bar{t}c$(or $t\bar{c}$) in the context of topcolor-assisted technicolor(TC2) models. We find that the contributions of charged scalars (technipions and top-pions) and topcolor gauge bosons are negligibly small. The neutral scalars (top-pion $\pi_{t}^{0}$ and top-Higgs $h_{t}^{0}$) can give significant contributions to this process. With reasonable values of the parameters in TC2 models, there will be several tens of the observable $\bar{t}c$ events to be generated in the future $e^{+}e^{-}$ linear colliders.

Rare top decayt→cgin top-color assisted technicolor models

In the framework of topcolor-assisted technicolor(TC2) models, we calculate the contributions of flavor changing scalar couplings involved the neutral top-pion $\pi_{t}^{0}$ and top-Higgs $h_{t}^{0}$ to the branching ratio $B_{r}(t\longrightarrow cg)$. We find that the value of $B_{r}(t\longrightarrow cg)$ can reach $ 1\times10^{-3}$ with reasonable values of the parameters in TC2 models, which may be testable in the future experiments.

Topcolour-assistedtechnicolour models and the muon anomalous magneticmoment

We discuss and estimate the contributions of the newparticles predicted by topcolour-assisted technicolour(TC2) models to the muon anomalous magnetic momentaµ. Our results show that the contributions ofpseudo-Goldstone bosons are very small and can be safelyignored. The main contributions come from the ETC gaugeboson xµ and topcolour gauge boson Z'.If we demand that the mass of Z' is consistentwith other experimental constraints, its contributionsare smaller than that of xµ. With reasonablevalues of the parameters in TC2 models, the observed BNLresults foraµ could be explained.