# AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling

## Abstract

The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling {alpha}{sub s}{sup Ads} (Q{sup 2}) which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of themore »

- Authors:

- Publication Date:

- Research Org.:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 979043

- Report Number(s):
- SLAC-PUB-13998

arXiv:1002.4660; TRN: US1003079

- DOE Contract Number:
- AC02-76SF00515

- Resource Type:
- Conference

- Resource Relation:
- Conference: Invited talk at International Workshop on Strong Coupling Gauge Theories in LHC Era: SCGT 09, Nagoya, Japan, 8-11 Dec 2009

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; APPROXIMATIONS; BARYON SPECTROSCOPY; BARYONS; BOUND STATE; DUALITY; EFFECTIVE CHARGE; EIGENVALUES; EQUATIONS OF MOTION; FORM FACTORS; HADRONS; HAMILTONIANS; HOLOGRAPHY; MESONS; PROBABILITY; QUANTUM CHROMODYNAMICS; QUARKS; SPACE-TIME; SPECTRA; SUM RULES; WAVE EQUATIONS; Phenomenology-HEP,HEPPH, HEPTH

### Citation Formats

```
Brodsky, Stanley J, /SLAC, de Teramond, Guy, /Costa Rica U., Deur, Alexandre, and /Jefferson Lab.
```*AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling*. United States: N. p., 2010.
Web.

```
Brodsky, Stanley J, /SLAC, de Teramond, Guy, /Costa Rica U., Deur, Alexandre, & /Jefferson Lab.
```*AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling*. United States.

```
Brodsky, Stanley J, /SLAC, de Teramond, Guy, /Costa Rica U., Deur, Alexandre, and /Jefferson Lab. Thu .
"AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling". United States. https://www.osti.gov/servlets/purl/979043.
```

```
@article{osti_979043,
```

title = {AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling},

author = {Brodsky, Stanley J and /SLAC and de Teramond, Guy and /Costa Rica U. and Deur, Alexandre and /Jefferson Lab},

abstractNote = {The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling {alpha}{sub s}{sup Ads} (Q{sup 2}) which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2010},

month = {4}

}