Gauge--invariant field correlators in QCD at finite temperature

We study by numerical simulations on a lattice the behaviour of the gauge--invariant two--point correlation functions of the gauge field strengths across the deconfinement phase transition.Comment: 12 pages, LaTeX file, + 5 PS figures, uuencoded-tar-compresse

Field strength correlators in QCD at zero and non-zero temperature

We study, by numerical simulations on a lattice, the behaviour of the gauge--invariant field strength correlators in QCD both at zero temperature, down to a distance of 0.1 fm, and at finite temperature, across the deconfinement phase transition.Comment: Talk given at the ``High Energy Conference on Quantum Chromodynamics'', Montpellier (France), 4-12 July 1996 (QCD 96); 5 pages, LaTeX file, uses ``espcrc2.sty''+ 5 PS figure

Casimir scaling as a test of QCD vacuum

Recent accurate measurements of static potentials between sources in various representations of the gauge group SU(3) performed by G.Bali provide a crucial test of the QCD vacuum models and different approaches to confinement. The Casimir scaling of the potential observed for all measured distances implies strong suppression of higher cumulant contributions. The consequences for the instanton vacuum model and the spectrum of the QCD string are also discussed.Comment: LaTeX, 15 pages, 1 figur

Topological density fluctuations and gluon condensate around confining string in Yang-Mills theory

We study the structure of the confining string in Yang-Mills theory using the method of the field strength correlators. The method allows us to demonstrate that both the local fluctuations of the topological charge and the gluon condensate are suppressed in the vicinity of the string axis in agreement with results of lattice simulations.Comment: 10 pages, 3 figures, RevTeX 4.

On the dependence of the gauge-invariant field-strength correlators in QCD on the shape of the Schwinger string

We study, by numerical simulations on a lattice, the dependence of the gauge-invariant two-point field-strength correlators in QCD on the path used to perform the color parallel transport between the two points.Comment: 9 pages, LaTeX file, + 5 PS figures. Revised version (accepted for publication in Physics Letters B) with new comments on the result

Glueball and gluelump spectrum in abelian projected QCD

We study glueball and gluelump spectra calculated after abelian projection in both quenched and $N_f=2$ full QCD. The abelian projection is made after MA gauge fixing. We demonstrate that both spectra can be recovered despite the problem with positivity. We suggest the interpretation of some of the gluelump states in the language of the abelian projected theory.Comment: Lattice 2001(confinement), 3 page

Cross-amplification of microsatellite loci reveals multiple paternity in Halys pit viper (Gloydius halys)

For Halys pit viper (Gloydius halys) species-specific microsatellite primers are not available. We tested a set of twenty primer pairs, originally developed for various Crotalinae species, for cross-amplification with Gloydius halys. The level of allelic polymorphism was assessed for eight successfully amplified loci via genotyping of a population sample. Between three to 24 alleles per locus were recorded. We examined a female and seven of its embryos for multiple paternity using seven microsatellite loci. More than two paternal alleles were detected in two loci indicating that two or more fathers were involved. This is the first report of multiple paternity in the wild population of Crotalinae. The life history characteristics of Halys pit-viper that can be associated with multiple paternity are discussed

The decay of the observed JPC=1−+J^{PC}=1^{-+} (1400) and JPC=1−+J^{PC}=1^{-+}(1600) hybrid candidates

We study the possible interpretation of the two exotic resonances $J^{PC}= 1^{-+}$ at 1400 and 1600 MeV, claimed to be observed by BNL, decaying respectively into $\eta\pi$, $\eta'\pi$, $f_{1}\pi$ and $\rho\pi$. These objects are interpreted as hybrid mesons, in the quark-gluon constituent model using a chromoharmonic confining potentiel. The quantum numbers $J^{PC}I^{G} = 1^{-+} 1^{-}$ can be considered in a constituent model as an hybrid meson ($q \bar q g$). The lowest $J^{PC}= 1^{-+}$states may be built in two ways : $l_{g}$=1 (gluon-excited) corresponding to an angular momentum between the gluon and ($q \bar q$) system, while $l_{q \bar q}=1$ (quarks-excited) corresponds to an angular momentum between $q$ and $\bar q$. For the gluon-excited mode $1^{-+}$ hybrids, we find the decay dominated by the $b_{1}\pi$ channel, and by the $\rho \pi$ channel for the quark-excited mode. In our model, neither the quark-excited nor the gluon-excited $1^{-+}$ (1400 MeV) hybrids can decay into $\eta\pi$ and $\eta'\pi$, in contradiction with experiment. Hence, the 1400 MeV resonance seems unlikely to be an hybrid state. The $1^{-+}$ (1600 MeV) gluon-excited hybrid is predicted with too large a total decay width, to be considered as an hybrid candidate. On the contrary the quark-excited mode has a total decay width around 165 MeV, with a $\rho \pi$ preferred decay channel, in agreement with BNL. Our conclusion is that {\it{this resonance may be considered as a hybrid meson in the quark-excited mode}}Comment: 13 pages, 1 figur

Field strength correlators in full QCD

We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant two-point correlation functions of the gauge field strengths in the QCD vacuum with dynamical fermions.Comment: 11 pages, LaTeX file, + 2 PS figure