251 research outputs found
Conformal Barrier and Hidden Local Symmetry Constraints: Walking Technirhos in LHC Diboson Channels
We expand the previous analyses of the conformal barrier on the walking
technirho for the 2 TeV diboson excesses reported by the ATLAS collaboration,
with a special emphasis on the hidden local symmetry (HLS) constraints. We
first show that the Standard Model (SM) Higgs Lagrangian is equivalent to the
scale-invariant nonlinear chiral Lagrangian, which is further gauge equivalent
to the scale-invariant HLS model, with the scale symmetry realized nonlinearly
via SM Higgs as a (pseudo-) dilaton. The scale symmetry forbids the new vector
boson decay to the 125 GeV Higgs plus W/Z boson, in sharp contrast to the
conventional "equivalence theorem" which is invalidated by the conformality.
The HLS forbids mixing between the iso-triplet technirho's, rho_{Pi} and
rho_{P}, of the one-family walking technicolor (with four doublets
N_D=N_F/2=4), which, without the HLS, would be generated when switching on the
standard model gauging. We also present updated analyses of the walking
technrho's for the diboson excesses by fully incorporating the constraints from
the conformal barrier and the HLS as well as possible higher order effects:
still characteristic of the one-family walking technirho is its smallness of
the decay width, roughly of order Gamma/M_rho ~ [3/N_C x 1/N_D] x
[Gamma/M_rho]_{QCD} ~ 70 GeV/2TeV (N_D= N_C=4), in perfect agreement with the
expected diboson resonance with Gamma<100 GeV. The model is so sharply
distinguishable from other massive spin 1 models without the conformality and
HLS that it is clearly testable at the LHC Run II. If the 2 TeV boson decay to
WH/ZH is not observed in the ongoing Run II, then the conformality is operative
on the 125 GeV Higgs, strongly suggesting that the 2 TeV excess events are
responsible for the walking technirhos and the 125 GeV Higgs is the
technidilaton.Comment: latex, 12 eps figures, 36 pages; minor corrections made in theory
part, version published in NP
Condensate Enhancement and D-Meson Mixing in Technicolor Theories
Since the pioneering work of Eichten and Lane it has been known that the
scale of the interactions responsible for the generation of the strange-quark
mass in extended technicolor theories must, absent any "GIM-like" mechanism for
suppressing flavor-changing neutral currents, be greater than of order 1000
TeV. In this note we point out that the constraint from the neutral D-meson
system is now equally strong, implying that the charm quark mass must also
arise from flavor dynamics at a scale this high. We then quantify the degree to
which the technicolor condensate must be enhanced in order to yield the
observed quark masses, if the extended technicolor scale is of order 1000 TeV.
Our results are intended to provide a framework in which to interpret and apply
the results of lattice studies of conformal strongly interacting gauge
theories, and the corresponding numerical measurements of the anomalous
dimension of the mass operator in candidate theories of "walking" technicolor.Comment: 6 pages, references added and re-ordere
Flavor constraints in a Bosonic Technicolor model
Flavor constraints in a bosonic Technicolor model are considered. We
illustrate different sources for their origin, and emphasize in particular the
role played by the vector states present in the Technicolor model. This feature
is the essential difference in comparison to an analogous model with two
fundamental Higgs scalar doublets.Comment: 16 pages, 13 figure
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