Recent results from the UKQCD Collaboration’s dynamical simulations are presented. The main feature of these ensembles is that they have a fixed lattice spacing and volume, but varying sea quark mass from infinite (corresponding to the quenched simulation) down to roughly that of the strange quark mass. The main aim of this work is to uncover dynamical quark effects from these “matched” ensembl...

It is shown that the quark mass density-dependent model can not be used to explain the process of the quark deconfinement phase transition because the quark confinement is permanent in this model. A quark mass densityand temperature-dependent model in which the quark confinement is impermanent has been suggested. We argue that the vacuum energy density B is a function of temperature and satisfi...

This note discusses some of the theoretical issues involved in the determination of quark masses. Unlike the leptons, quarks are connned inside hadrons and are not observed as physical particles. Quark masses cannot be measured directly, but must be determined indirectly through their innuence on hadron properties. As a result, the values of the quark masses depend on precisely how they are dee...

Some simple relations between unpolarized and polarized quark parton distributions have direct experimental consequences which will be presented here. In particular, we will see that it is possible to relate the deep inelastic structure functions F2 and g1, both for proton and deuteron, in fair agreement with experimental data. Key-Words : polarized parton densities, deep-inelastic scattering. ...

We analyze the process e p → e p φ near the threshold within uud-ss̄ cluster model as a probe of the strangeness content of proton. Our consideration is based on the relativistic harmonic oscillator quark model which takes into account the Lorentz-contraction effect of the hadron wavefunctions. We find that the knockout mechanisms are comparable to the diffractive production of vector-meson-domi...

We explore the opportunity to look for quark compositeness in the early stages of the LHC running by analyzing high-E T dijet production. The quark substructure that will manifest itself by affecting various kinematic distributions at the center-of-mass energy E cm =10 TeV and in the integrated luminosity range from 0.5 to 10 fb −1 is investigated. The estimation of the characteristic energy sc...

Quark-hadron duality addresses some of the most fundamental issues in strong interaction physics, in particular the nature of the transition from the perturbative to non-perturbative regions of QCD. I summarize recent developments in quark-hadron duality in lepton–hadron scattering, and outline how duality can be studied at future high-luminosity facilities such as Jefferson Lab at 12 GeV or an...

Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotropic calculation fits the light element abundances ranging from 1H at 76% and 4He at 24% by mass through 2H and 3He at parts in 105 do...

Our previous calculations of the seaand valence-quark mass dependence of the pseudoscalar meson masses and decay constants is repeated on a 163 · 32 lattice which allows for a better determination of the quantities in question. The conclusions are similar as before on the 164 lattice [1]. The two light dynamical quark flavours we simulate have masses in the range 1 4ms < mu,d < 2 3ms. The sea q...