# QCD and Light-Front Dynamics

## Abstract

AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its {beta}-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-frontmore »

- Authors:

- Publication Date:

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

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1002997

- Report Number(s):
- SLAC-PUB-14275

arXiv:1010.4962; TRN: US1100770

- DOE Contract Number:
- AC02-76SF00515

- Resource Type:
- Conference

- Resource Relation:
- Conference: Invited talk at Light Cone 2010: Relativistic Hadronic and Particle Physics (LC2010), Valencia, Spain, 14-18 Jun 2010

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; BOUND STATE; CONDENSATES; CONFINEMENT; DIMENSIONS; EIGENSTATES; FIELD THEORIES; GLUONS; HADRONS; HAMILTONIANS; HOLOGRAPHY; LIGHT CONE; ORBITAL ANGULAR MOMENTUM; PHYSICS; PROBABILITY; PROTONS; QUANTUM CHROMODYNAMICS; QUARKS; SCHROEDINGER EQUATION; SPIN; Phenomenology-HEP, Theory-HEP,HEPPH, HEPTH

### Citation Formats

```
Brodsky, Stanley J, de Teramond, Guy F, and /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.
```*QCD and Light-Front Dynamics*. United States: N. p., 2011.
Web.

```
Brodsky, Stanley J, de Teramond, Guy F, & /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.
```*QCD and Light-Front Dynamics*. United States.

```
Brodsky, Stanley J, de Teramond, Guy F, and /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U. Mon .
"QCD and Light-Front Dynamics". United States. https://www.osti.gov/servlets/purl/1002997.
```

```
@article{osti_1002997,
```

title = {QCD and Light-Front Dynamics},

author = {Brodsky, Stanley J and de Teramond, Guy F and /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.},

abstractNote = {AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its {beta}-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include QCD interaction terms. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2011},

month = {1}

}