The light-front (LF) quantization of QCD in light-cone gauge has a number ofremarkable advantages, including explicit unitarity, a physical Fock expansion,the absence of ghost degrees of freedom, and the decoupling properties neededto prove factorization theorems in high momentum transfer inclusive andexclusive reactions. We present a systematic study of LF-quantized gauge theoryfollowing the Dirac method and construct the Dyson-Wick S-matrix expansionbased on LF-time-ordered products. The free theory gauge field is shown tosatisfy the Lorentz condition as an operator equation as well as the light-conegauge condition. Its propagator is found to be transverse with respect to bothits four-momentum and the gauge direction. The interaction Hamiltonian of QCDcan be expressed in a form resembling that of covariant theory, except foradditional instantaneous interactions which can be treated systematically. Therenormalization constants in YM theory are shown to satisfy the identity$Z_1=Z_3$ at one loop order. The QCD $\beta$ function computed in thenoncovariant light-cone gauge agrees with that known in the conventionalframework. Some comments on the relationship of our LF framework, with thedoubly transverse gauge propagator, to the analytic effective charge andrenormalization scheme defined by the pinch technique, the unitarity relationsand the spectral representation are also made. LF quantization thus provides aconsistent formulation of gauge theory, despite the fact that the hyperplanes$x^{\pm}=0$ used to impose boundary conditions constitute characteristicsurfaces of a hyperbolic partial differential equation.
展开▼
