Eur. Phys. J. A (2007) 31: 638-644
https://doi.org/10.1140/epja/i2006-10221-7

QNP 2006

Hadron spectroscopy and structure from AdS/CFT

Stanford Linear Accelerator Center, Stanford University, 94309, Stanford, CA, USA

^* e-mail: sjbth@slac.stanford.edu

Received: 8 November 2006
Accepted: 15 November 2006
Published online: 5 March 2007

Abstract

The AdS/CFT correspondence between conformal field theory and string states in an extended space-time has provided new insights into not only hadron spectra, but also their light-front wave functions. We show that there is an exact correspondence between the fifth-dimensional coordinate of anti-de Sitter space z and a specific impact variable ζ which measures the separation of the constituents within the hadron in ordinary space-time. This connection allows one to predict the form of the light-front wave functions of mesons and baryons, the fundamental entities which encode hadron properties and scattering amplitudes. A new relativistic Schrödinger light-front equation is found which reproduces the results obtained using the fifth-dimensional theory. Since they are complete and orthonormal, the AdS/CFT model wave functions can be used as an initial ansatz for a variational treatment or as a basis for the diagonalization of the light-front QCD Hamiltonian. A number of applications of light-front wave functions are also discussed.