Deog Ki Hong

Chiral dynamics of baryons from string theory

We study baryons in a holographic model of QCD by Sakai and Sugimoto, realized as small instantons with fundamental string hairs. We introduce an effective field theory of the baryons in the five-dimensional setting, and show that the instanton interpretation implies a particular magnetic coupling. Dimensional reduction to four dimensions reproduces the usual chiral effective action, and, in particular, we estimate the axial coupling

Composite Higgs from higher representations

{g}_{A}

Baryons in AdS/QCD

between baryons and pions and the magnetic dipole moments, both of which are proportional to

Holographic estimate of oblique corrections for technicolor

{N}_{c}

Spin 3/2 baryons and form factors in AdS/QCD

. We extrapolate to finite

RG analysis of magnetic catalysis in dynamical symmetry breaking

{N}_{c}

The electric dipole moment of the nucleons in holographic QCD

and discuss subleading corrections.

Pseudo scalar contributions to light-by-light correction of muon g−2 in AdS/QCD

We investigate new models of dynamical electroweak symmetry breaking resulting from the condensation of fermions in higher representations of the technicolor group. These models lie close to the conformal window, and are free from the flavor-changing neutral current problem despite small numbers of flavors and colors. Their contribution to the S parameter is small and not excluded by precision data. The Higgs itself can be light and narrow.

The superstring, diff S1/S1, and holomorphic geometry

Abstract We construct a holographic model for baryons in the context of AdS/QCD and study the spin- 1 2 nucleon spectra and its couplings to mesons, taking full account of the effects from the chiral symmetry breaking. A pair of 5D spinors is introduced to represent both left and right chiralities. Our model contains two adjustable parameters, the infrared cutoff and the Yukawa coupling of bulk spinors to bulk scalars, corresponding to the order parameter of chiral symmetry. Taking the lowest-lying nucleon mass as an input, we calculate the mass spectrum of excited nucleons and the nucleon couplings to pions. The excited nucleons show a parity-doubling pattern with smaller pion–nucleon couplings.

HOLOGRAPHIC ASPECTS OF THREE DIMENSIONAL QCD FROM STRING THEORY

We study the oblique corrections to the electroweak interaction in the holographic model of technicolor theories. The oblique