Holographic Modelling of a Light Techni-Dilaton
arXiv:1302.4553 · doi:10.1103/PhysRevD.87.086003
Abstract
We present a simplified holographic model of chiral symmetry breaking in gauge theory. The chiral condensate is represented by a single scalar field in AdS, with the gauge dynamics input through radial dependence of its mass, representing the running of the anomalous dimension of the qbar q operator. We discuss simple examples of the chiral transition out of the conformal window when the infrared value of the anomalous dimension, γ_m, is tuned to one (equivalently the AdS-scalar mass squared is tuned to the Breitenlohner-Freedman bound of -4). The output of the model are the masses of the scalar meson bound states. We show in an explicit example that if the gradient of the running of the anomalous dimension falls to zero at the scale where the BF bound violation occurs, so that the theory becomes near conformal, then the theory possesses a techni-dilaton state that is parametrically lighter than the dynamically generated quark mass. Indeed the full spectrum of excited meson states also become light (relative to the techni-quark mass) as they approach a conformal spectrum.
8 pages, 8 pdf figures, added discussion of Fig 3 and new references
References in corpus (11)
- Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
- Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
- Light scalar at LHC: the Higgs or the dilaton?
- Supersymmetry Inspired QCD Beta Function
- Zero of the discrete beta function in SU(3) lattice gauge theory with color sextet fermions
- Nearly conformal gauge theories in finite volume
- Conformal Windows of SU(N) Gauge Theories, Higher Dimensional Representations and The Size of The Unparticle World
- A Light Dilaton in Walking Gauge Theories
- A Very Light Dilaton
- Holography of a Composite Inflaton
- S-parameter, Technimesons, and Phase Transitions in Holographic Tachyon DBI Models