We formulate a scale-invariant hidden local symmetry (HLS) as a low-energy effective theory of walking technicolor (WTC) which includes the technidilaton, technipions, and technirho mesons as the low-lying spectra. As a benchmark for LHC phenomenolog
y, we in particular focus on the one-family model of WTC having eight technifermion flavors, which can be, at energy scales relevant to the reach of the LHC, described by the scale-invariant HLS based on the manifold $[SU(8)_L times SU(8)_R]_{rm global} times SU(8)_{rm local}/SU(8)_V$, where $SU(8)_{rm local}$ is the HLS and the global $SU(8)_L times SU(8)_R$ symmetry is partially gauged by $SU(3) times SU(2)_L times U(1)_Y$ of the standard model. Based on the scale-invariant HLS, we evaluate the coupling properties of the technirho mesons and place limits on the masses from the current LHC data. Then, implications for future LHC phenomenology are discussed by focusing on the technirho mesons produced through the Drell-Yan process. We find that the color-octet technirho decaying to the technidilaton along with the gluon is of interest as the discovery channel at the LHC, which would provide a characteristic signature to probe the one-family WTC.
We calculate masses of the technipions in the walking technicolor model with the anomalous dimension gamma_m =1, based on a holographic model which has a naturally light technidilaton phi as a composite Higgs with mass m_phi simeq 125 GeV. The one-fa
mily model (with 4 weak-doublets) is taken as a concrete example in such a framework, with the inputs being F_pi=v/2 simeq 123 GeV and m_phi simeq 125 GeV as well as gamma_m=1. It is shown that technipion masses are enhanced by the large anomalous dimension to typically O(1) TeV. We find a correlation between the technipion masses and S^{(TC)}, the S parameter arising only from the technicolor sector. The current LHC data on the technipion mass limit thus constrains S^{(TC)} to be not as large as O(1), giving a direct constraint on the technicolor model building. This is a new constraint on the technicolor sector alone quite independent of other sector connected by the extended-technicolor-type interactions, in sharp contrast to the conventional S parameter constraint from the precision electroweak measurements.
We study gluonic effects (gluon condensation effects) on the hadronic leading order (HLO) contributions to the anomalous magnetic moment (g-2) of leptons, based on a holographic model having explicit gluonic mode introduced for consistency with the o
perator product expansion of QCD. We find gluonic enhancement of HLO contributions to the muon g-2 by about 6%, which nicely fills in the gap between the holographic estimate without gluonic effects and the phenomenological one using the experimental data as inputs. Similar calculations including the gluonic effects for the electron and the tau lepton g-2 are also carried out in good agreement with the phenomenological estimates. We then apply our holographic estimate to the Walking Technicolor (WTC) where large techni-gluonic effects were shown to be vital for the Technidilaton, (pseudo) Nambu-Goldstone boson of the (approximate) scale symmetry of WTC, to be naturally as light as 125 GeV. It is shown that the value of the techni-HLO contributions to the muon g-2 is 10-100 times enhanced by inclusion of the same amount of the gluonic effects as that realizing the 125 GeV Technidilaton, although such an enhanced techni-HLO contribution is still negligibly small compared with the current deviation of the Standard Model prediction of the muon g-2 from the experiments. The techni-HLO contributions to the tau lepton g-2 is also discussed, suggesting a possible phenomenological relevance to be tested by the future experiments.
We complete the list of one loop renormalization group equations and matching conditions relevant for the computation of the electroweak precision parameters $S$ and $T$ in the three site Higgsless model. We obtain one-loop formulas for $S$ and $T$ e
xpressed in terms of physical observables such as the KK gauge boson mass $M_{W}$, the KK fermion mass $M$, and the KK gauge boson ($W$) couplings with light quarks and leptons $g_{Wff}$. It is shown that these physical observables, $M_{W}$, $M$ and $g_{Wff}$ are severely constrained by the electroweak precision data. Unlike the tree level analysis on the ideally delocalized fermion, we find that perfect fermiophobity of $W$ is ruled out by the precision data. We also study the cutoff dependence of our analysis. Although the model is non-renormalizable, the dependence on the cutoff parameter $Lambda$ is shown to be non-significant.
