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...

We describe our methods for performing quantum chromodynamics (QCD) simulations that sustain up to 20% of the peak performance on BlueGene supercomputers. We present our methods, scaling properties, and first cutting edge results relevant to QCD. We show how this enables unprecedented computational scale that brings lattice QCD to the next generation of calculations. We present our QCD simulati...

The Perturbative QCD Potential and the t ¯ t Threshold Abstract We include the full second-order corrections to the static QCD potential in the analysis of the t ¯ t threshold cross section. There is an unexpectedly large difference between the QCD potential improved by the renormalization-group equation in momentum space and the potential improved by the renormalization-group equation in coord...

We discuss QCD in the Hamiltonian frame work. We treat finite density QCD in the strong coupling regime. We present a parton-model inspired regularisation scheme to treat the spectrum (θ-angles) and distribution functions in QED 1+1. We suggest a Monte Carlo method to construct low-dimensionasl effective Hamiltonians. Finally, we discuss improvement in Hamiltonian QCD. 1. Introduction There are...

We review the calculation of moments of both the polarized and unpolarized parton distribution functions of the nucleon in lattice QCD, and in particular their extrapolation to the physical region. We also discuss the reconstruction of the x dependence of the valence quark distributions in the nucleon from a finite number of lattice moments.

We study Λ QCD /m B corrections to factorization in B → Kπ decays. First, we analyze these decay channels within factorization, showing that, irrespectively of the value of γ, it is not possible to reproduce the experimental data. Then, we discuss Λ QCD /m B corrections to these processes, and argue that there is a class of doubly Cabibbo enhanced non-factorizable contributions, usually called ...

I review recent Lattice results. In particular, the confinement mechanism and string breaking, glueballs and hybrid mesons as well as light hadron spectroscopy are discussed.

We test the quark mass dependence implemented in the quasiparticle dispersion relations of our quasiparticle model for the QCD equation of state by comparing with recently available lattice QCD data near Tc employing almost physical quark masses. In addition, we emphasize the capability of our model to successfully describe lattice QCD results for imaginary chemical potential and to analyticall...

The H-dibaryon, a J = 0 state with the valence quark content udsuds, has long been hypothesised to exist because of the attractive nature of colour magnetic gluon exchange in the flavoursinglet channel. Using lattice QCD the NPLQCD collaboration have investigated this system and evidence is presented for the existence of a stable H-dibaryon, albeit at a quark mass somewhat larger than that in n...

Parity and avor symmetry is not broken in QCD. Using this fact, we propose a new method to measure the chiral condensate in lattice QCD using Wilson fermions with an operator that breaks parity and avor in addition to the chiral symmetry.