193 research outputs found
Walking on the Ladder: 125 GeV Technidilaton, or Conformal Higgs -Dedicated to the late Professor Yoichiro Nambu-
The walking technicolor based on the ladder Schwinger-Dyson gap equation is
studied, with the scale-invariant coupling being an idealization of the
Caswell-Banks-Zaks infrared fixed point in the "anti-Veneziano limit", such
that with fixed and
fixed (), of the gauge theory with massless
flavors near criticality. We show that the 125 GeV Higgs can be naturally
identified with the technidilaton (TD) predicted in the walking technicolor, a
pseudo Nambu-Goldstone (NG) boson of the spontaneous symmetry breaking of the
approximate scale symmetry. Ladder calculations yield the TD mass from
the trace anomaly as , independently of
the renormalization point , where is the dynamical mass of the
technifermion, and the TD decay
constant. It reads , ( GeV),
which implies for in the one-family model (), in
good agreement with the current LHC Higgs data. The result reflects a generic
scaling as a vanishing trace anomaly, namely the TD has a
mass vanishing in the anti-Veneziano limit, similarly to meson as
a pseudo-NG boson of the ordinary QCD with vanishing anomaly in the
Veneziano limit ().Comment: revtex4, 36 pages, 7 eps figures, some corrections made, references
added; a version to appear in JHEP; typo correcte
Parameter in the Holographic Walking/Conformal Technicolor
We explicitly calculate the parameter in entire parameter space of the
holographic walking/conformal technicolor (W/C TC), based on the deformation of
the holographic QCD by varying the anomalous dimension from
through continuously. The parameter is given as a
positive monotonic function of which is fairly insensitive to
and continuously vanishes as when , where
is the vacuum expectation value of the bulk scalar field at the infrared
boundary of the 5th dimension and is related to the mass of (techni-)
meson () and the decay constant () as for . However, although is related to the
techni-fermion condensate \condense, we find no particular suppression of
and hence of due to large , based on the correct
identification of the renormalization-point dependence of \condense in
contrast to the literature. Then we argue possible behaviors of
as \condense \to 0 near the conformal window characterized by the Banks-Zaks
infrared fixed point in more explicit dynamics with . It is
a curious coincidence that the result from ladder Schwinger-Dyson and
Bethe-Salpeter equations well fits in the parameter space obtained in this
paper. When is realized, the holography suggests a novel
possibility that vanishes much faster than the dynamical mass does.Comment: typo, a version to be published in Progress of Theoretical Physic
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