With the help of M-theory configuration of N=1 supersymmetric QCD, we analyze the strong coupling moduli of N=1 theory and its relation with S-duality transformation in N=2 supersymmetric QCD. As a result we confirm that two type-IIA descriptions for N=1 supersymmetric QCD, one of them being strong coupling description and another being weak, correspond to a single M-theory description for N=1 ...

One of the major frontiers of lattice field theory is the inclusion of light fermions in simulations, particularly in pursuit of accurate, first principles predictions from lattice QCD. With dedicated Teraflops-scale computers currently simulating QCD, another step towards precision full QCD simulations is underway. In addition to ongoing staggered and Wilson fermion simulations, first results ...

We review recent theoretical developments in heavy quarkonium physics from the point of view of Effective Field Theories of QCD. We discuss Non-Relativistic QCD and concentrate on potential Non-Relativistic QCD. Our main goal will be to derive QCD Schrödinger-like equations that govern heavy quarkonium physics in the weak and strong coupling regime. We also discuss a selected set of application...

We show that the minimal Gaussian model of nonlocal vacuum quark and quark-gluon condensates in QCD generates the non-transversity of vector current correlators. We suggest the improved Gaussian model of the nonperturbative QCD vacuum, which respects QCD equations of motion and minimizes the revealed gauge-invariance breakdown. We obtain the refined values of pion distribution amplitude (DA) co...

We construct a classical vortex string solution in a Seiberg-dual theory of N = 1 supersymmetric SO(Nc) QCD which flows to a confining phase. We claim that this vortex string is a QCD string, as previouly argued by M. Strassler. In SO(Nc) QCD, it is known that stable QCD strings exist even in the presence of dynamical quarks. We show that our vortex strings are stable in the Seiberg-dual theory.

We present skeleton-motivated evaluation of QCD observables. The approach can be applied in analytic versions of QCD in certain classes of renormalization schemes. We present two versions of analytic QCD which can be regarded as low-energy modifications of the “minimal” analytic QCD and which reproduce the measured value of the semihadronic τ decay ratio rτ . Further, we describe an approach of...

The lattice QCD studies indicate that the critical temperature Tc ≃ 260 − 280 MeV of the deconfinement phase transition in quenched QCD is considerably smaller than the lowest-lying glueball mass mG ≃ 1500 − 1700 MeV, i.e., Tc ≪ mG. As a consequence of this large difference, the thermal excitation of the glueball in the confinement phase is strongly suppressed by the statistical factor as eGc ≃...

Using recent measurements of the b-quark fragmentation distribution obtained in e+e− → bb events registered at the Z pole, the non-perturbative QCD component of the distribution has been extracted independently of any hadronic physics modelling. This distribution depends only on the way the perturbative QCD component has been defined. When the perturbative QCD component is taken from a parton s...