Minimal Walking Technicolour, the Top Mass and Precision Electroweak Measurements
N. Evans, F. Sannino
TL;DR
This work investigates a minimal walking technicolor model based on SU(2) with two adjoint technifermions and demonstrates its natural embedding into an extended technicolor framework to generate the top quark mass. By analyzing the two-loop beta function and critical coupling, the authors argue the theory sits near the conformal window, enabling walking dynamics that mitigate typical precision EW constraints. An SU(4)$_{ETC}$ realization is explored, showing how ETC breaking to $SO(3)_{TC}\times U(1)_Y$ can feed the technicolor condensate to the fourth-family leptons and, via walking, enhance the top mass, with the potential to extend to additional families. Precision data allow modest positive shifts in $S$ and $T$, and the estimated contributions can be consistent with current measurements for a Higgs mass in the debated range; thus the model is not ruled out and remains testable at the LHC.
Abstract
We consider a minimal technicolour theory with two techniflavours in the adjoint representation of an SU(2) technicolour gauge group which has been argued to feature walking dynamics. We show how to naturally embed this theory in an extended technicolour model capable of generating the top quark mass. We investigate the precision constraints and conclude that such models, in the light of the most recent precision data fit, are not ruled out.