In this work we study the zero-charge sector of massive two-dimensional Quantum Chromodynamics in the decoupled formulation. We find that some general features of the massless theory, concerning the constraints and the rightand left-moving character of the corresponding BRST currents, survive in the massive case. The implications for the integrability properties previously valid in the massless...

I review recent progress on the connection between string theory and quantum chromodynamics in the context of the gauge/gravity duality. Emphasis is placed on conciseness and conceptual aspects rather than on technical details. Topics covered include the largeNc limit of gauge theories, the gravitational description of gauge theory thermodynamics and hydrodynamics, and confinement/deconfinement...

We review the recent glueball mass calculations using an efficient method for solving the Schrödinger equation order by order with a scheme preserving the continuum limit. The reliability of the method is further supported by new accurate results for (1+1)-dimensional σ models and (2+1)-dimensional non-abelian models. We present first and encouraging data for the glueball masses in 3+1 dimensio...

I review the light-cone Fock state represention and its associated light-cone factorization scheme as a method for encoding the flavor, momentum, and helicity properties of hadrons in the form of universal process-independent and frame-independent amplitudes. Discrete light-cone quantization (DLCQ) provides a matrix representation of the QCD Hamiltonian and a nonperturbative method for computin...

The theory of strong interactions, quantum chromodynamics (QCD), is quite successful in the prediction and description of main features of multiparticle production processes at high energies. The general perturbative QCD approach to these processes (mainly to e + e −-annihilation) is briefly formulated and its problems are discussed. It is shown that the analytical calculations at the parton le...

Despite the many empirical successes of QCD, there are a number of intriguing experimental anomalies that have been observed in heavy flavor hadroproduction, in measurements of azimuthal correlations in deep inelastic processes, and in measurements of spin correlations in hadronic reactions. Such phenomena point to color coherence and multiparton correlations in the hadron wavefunctions and phy...

The two topics are (1) estimates of perturbation theory coefficients for R (e+e+ hadrons), and (2) th e virtual-photon structure function, with emphasis on the analytic behavior in its squared mass.

A pedagogical introduction to the heavy quark theory is given. It is explained that various expansions in the inverse heavy quark mass 1=mQ present a version of the Wilson operator product expansion in QCD. A systematic approach is developed and many practically interesting problems are considered. I show how the 1=mQ expansions can be built using the background eld technique and how they work ...