The AdS/CFT Correspondence and Novel Effects in QCD

Stanley J. Brodsky

Stanford University and SLAC

One of the most interesting recent advances in hadron physics has been the application of AdS/CFT correspondence to quantum chromodynamics. Although QCD is not a conformally invariant field theory, one can nevertheless use the mathematical representation of the conformal group in five-dimensional anti-de Sitter space to construct an analytic first approximation to the theory. The resulting AdS/QCD model gives accurate predictions for hadron spectroscopy and a description of the quark structure of mesons and baryons which has scale invariance and dimensional counting at short distances, together with color confinement at large distances. In addition, one can compute the form of the frame-independent light-front bound-state wavefunctions, the fundamental nonperturbative entities which encode hadron properties and which allow the computation of hadronic scattering amplitudes. A number of applications of light-front wavefunctions to QCD phenomenology will be discussed, such as color transparency, hidden color, intrinsic charm, sea-quark asymmetries, dijet diffraction, direct hard processes, and spin dynamics.