Magnetic charge superselection in the deconfined phase of Yang-Mills theory

The vacuum expectation value of an operator carrying magnetic charge is studied numerically for temperatures above the deconfinement temperature in SU(2) and SU(3) gauge theory. By analyzing its finite size behaviour, this is found to be exactly zero in the thermodynamical limit for any T > T_c whenever the magnetic charge of the operator is different from zero. These results show that magnetic charge is superselected in the hot phase of quenched QCD.Comment: 4 pages, 6 figures, revtex

Gauge-invariant quark-antiquark nonlocal condensates in lattice QCD

We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant quark-antiquark nonlocal condensates in the QCD vacuum with dynamical fermions. A determination is also done in the quenched approximation and the results are compared with the full-QCD case. The fermionic correlation length is extracted and compared with the analogous gluonic quantity.Comment: 14 pages, LaTeX file, + 6 PS figure

Renormalization and topological susceptibility on the lattice: SU(2) Yang-Mills theory

The renormalization functions involved in the determination of the topological susceptibility in the SU(2) lattice gauge theory are extracted by direct measurements, without relying on perturbation theory. The determination exploits the phenomenon of critical slowing down to allow the separation of perturbative and non-perturbative effects. The results are in good agreement with perturbative computations.Comment: 12 pages + 4 figures (PostScript); report no. IFUP-TH 10/9

Color confinement and dual superconductivity in full QCD

We report on evidence that confinement is related to dual superconductivity of the vacuum in full QCD, as in quenched QCD. The vacuum is a dual superconductor in the confining phase, whilst the U(1) magnetic symmetry is realized a la Wigner in the deconfined phase.Comment: 4 pages, 4 eps figure

New records of <i>Catamblyrhynchus diadema</i> for Northwestern Argentina

The first record of the Plushcap ( <i>Catamblyrhynchus diadema</i>) for Salta province is given based in a collected specimen. New records for Jujuy province are reported. A immature plumage is described and information about the habits is discussed by means ofthe bibliography and field notes

A critical comparison of different definitions of topological charge on the lattice

A detailed comparison is made between the field-theoretic and geometric definitions of topological charge density on the lattice. Their renormalizations with respect to continuum are analysed. The definition of the topological susceptibility, as used in chiral Ward identities, is reviewed. After performing the subtractions required by it, the different lattice methods yield results in agreement with each other. The methods based on cooling and on counting fermionic zero modes are also discussed.Comment: 12 pages (LaTeX file) + 7 (postscript) figures. Revised version. Submitted to Phys. Rev.

The relativity experiment of MORE: global full-cycle simulation and results

BepiColombo is a joint ESA/JAXA mission to Mercury with challenging objectives regarding geophysics, geodesy and fundamental physics. In particular, the Mercury Orbiter Radioscience Experiment (MORE) intends, as one of its goals, to perform a test of General Relativity. This can be done by measuring and constraing the post-Newtonian (PN) parameters to an accuracy significantly better than current one. In this work we perform a global full-cycle simulation of the BepiColombo Radio Science Experiments (RSE) in a realistic scenario, focussing on the relativity experiment but solving simultaneously for all the parameters of interest for RSE in a global least squares fit within a constrained multiarc strategy. The results on the achievable accuracy for each PN parameter will be presented and discussed

High energy parton-parton amplitudes from lattice QCD and the stochastic vacuum model

Making use of the gluon gauge-invariant two-point correlation function, recently determined by numerical simulation on the lattice in the quenched approximation and the stochastic vacuum model, we calculate the elementary (parton-parton) amplitudes in both impact-parameter and momentum transfer spaces. The results are compared with those obtained from the Kr\"{a}mer and Dosch ansatz for the correlators. Our main conclusion is that the divergences in the correlations functions suggested by the lattice calculations do not affect substantially the elementary amplitudes. Phenomenological and semiempirical information presently available on elementary amplitudes is also referred to and is critically discussed in connection with some theoretical issues.Comment: Text with 11 pages in LaTeX (twocolumn form), 10 figures in PostScript (psfig.tex used). Replaced with changes, Fig.1 modified, two references added, some points clarified, various typos corrected. Version to appear in Phys. Rev.