Friday 14 September, 11:00h, at Nikhef in H331
Speaker: Stan Brodsky (Stanford)
Title: Light-Front Holography: "An analytic approximation to hadron physics"
Abstract:
Gauge/gravity duality leads to a simple, analytical, and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian. This approach, called "Light-Front Holography", successfully describes the spectroscopy of light-quark meson and baryons, their elastic and transition form factors, and other hadronic properties. The bound-state Schrodinger and Dirac equations of the soft-wall AdS/QCD model predict linear Regge trajectories which have the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. Light-front holography connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable zeta in 3+1 space at fixed light-front time. A key feature is the determination of the frame-independent light-front wavefunctions of hadrons — the relativistic analogs of the Schrodinger wavefunctions of atomic physics which allow one to compute form factors, transversity distributions, spin properties of the valence quarks, jet hadronization, and other hadronic observables. AdS/QCD and Light-Front Holography provide a remarkable window into the dynamics and spectroscopy of hadrons, as well as color confinement. This approach also gives a new perspective on the correct definition of the vacuum and the interpretation of condensates in relativistic quantum field theory, thus resolving the 10^{45} conflict with the empirical value of the cosmological constant.
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