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DOE OSTI · 1002997

QCD and Light-Front Dynamics

Brodsky, Stanley J·de Teramond, Guy F
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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-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.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDSAMPLITUDESBOUND STATECONDENSATESCONFINEMENTDIMENSIONSEIGENSTATESFIELD THEORIESGLUONSHADRONSHAMILTONIANSHOLOGRAPHYLIGHT CONEORBITAL ANGULAR MOMENTUMPhenomenology-HEP, Theory-HEP,HEPPH, HEPTHPHYSICSPROBABILITYPROTONSQUANTUM CHROMODYNAMICSQUARKSSCHROEDINGER EQUATIONSPIN

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Brodsky, Stanley J, de Teramond, Guy F. 2011-01-10. QCD and Light-Front Dynamics. https://www.osti.gov/biblio/1002997

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