Quantum chromodynamics and other field theories on the light cone
Abstract
In recent years lightcone quantization of quantum field theory has emerged as a promising method for solving problems in the strong coupling regime. The approach has a number of unique features that make it particularly appealing, most notably, the ground state of the free theory is also a ground state of the full theory. We discuss the lightcone quantization of gauge theories from two perspectives: as a calculational tool for representing hadrons as QCD bound states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a computer. The lightcone Fock state expansion of wavefunctions provides a precise definition of the parton model and a general calculus for hadronic matrix elements. We present several new applications of lightcone Fock methods, including calculations of exclusive weak decays of heavy hadrons, and intrinsic heavyquark contributions to structure functions. A general nonperturbative method for numerically solving quantum field theories, “discretized lightcone quantization”, is outlined and applied to several gauge theories. This method is invariant under the large class of lightcone Lorentz transformations, and it can be formulated such that ultraviolet regularization is independent of the momentum space discretization. Both the boundstate spectrum and the corresponding relativistic lightcone wavefunctions can be obtained by matrix diagonalization and related techniques. We also discuss the construction of the lightcone Fock basis, the structure of the lightcone vacuum, and outline the renormalization techniques required for solving gauge theories within the Hamiltonian formalism on the light cone.
 Publication:

Physics Reports
 Pub Date:
 1998
 DOI:
 10.1016/S03701573(97)000896
 arXiv:
 arXiv:hepph/9705477
 Bibcode:
 1998PhR...301..299B
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 206 pages Latex, figures included, Submitted to Physics Reports