The leading nonperturbative QCD corrections to the one gluon exchange quark-quark, quark-antiquark and q ¯ q pair-excitation potentials are derived by using a covariant form of nonlocal two-quark and two-gluon vacuum expectation values. Our numerical calculation indicates that the correction of quark and gluon condensates to the quark-antiquark potential improves the heavy quarkonium spectra to...

Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks in instanton field allows simultaneously to explain some important features of lowand highenergy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavy-quark potential are briefly discussed within the instanto...

We investigate the production of gluon pairs from a space-time dependent classical chromofield via vacuum polarization within the framework of the background field method of QCD. The investigation of the production of gluon pairs is important in the study of the evolution of the quark-gluon plasma in ultra-relativistic heavy-ion collisions at RHIC and LHC.

The vacuum wave functional of Coulomb gauge Yang-Mills theory is determined within the vari-ational principle and used to calculate various Green functions and observables. The results show that heavy quarks are confined by a linearly rising potential and gluons cannot propagate over large distances. The 't Hooft loop shows a perimeter law and thus also indicates confinement.

We calculate the electric dipole moments of the neutron and the Λ within the framework of heavy baryon chiral perturbation theory. They are induced by strong CP-violating terms of the effective Lagrangian in the presence of the vacuum angle θ 0. The construction of such a Lagrangian is outlined and we are able to give an estimate for θ 0 .

The system of light quark and heavy antiquark source is studied in 1+1 QCD in the large N C limit. The situation is demonstrated to be the two dimensional analogue of the problem in 3+1 QCD corresponding to the essentially nonlocal case of zero vacuum correlation length, which does not allow perturbative treatment. The modified Fock–Schwinger gauge condition is employed to derive the effective ...

The system of light quark and heavy antiquark source is studied in 1+1 QCD in the large N C limit. The situation is demonstrated to be the two dimensional analogue of the problem in 3+1 QCD corresponding to the essentially nonlocal case of zero vacuum correlation length, which does not allow perturbative treatment. The modified Fock–Schwinger gauge condition is employed to derive the effective ...

Fully analytical results for the first two moments of the heavy-quark vacuum polarisation function at four loops in quantum chromo-dynamics are presented. PACS: 12.38.-t, 12.38.Bx, 13.66.Bc, 13.85.Lg ∗Permanent address: Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980, Dubna (Moscow region), Russia.

A straightforward calculation reveals the essentially nonlocal character of the leading heavy QQ̄ interaction arising from nonperturbative gluon field correlations in the model of a fluctuating QCD vacuum. In light of this quarkonium spin splitting ratio predictions which have supported the scalar confinement ansatz are reconsidered as a specific example of possible consequences for spectroscopy.

Heavy vacuum gas oil (HVGO) is a complex and viscous hydrocarbon stream that is produced as the bottom side product from the vacuum distillation units in petroleum refineries. HVGO is conventionally treated with thermochemical process, which is costly and environmentally polluting. Here, we investigate two petroleum biotechnology applications, namely valorization and bioupgrading, as green appr...