Vacuum Energy Density in the Quantum Yang - Mills Theory

Using the effective potential approach for composite operators, we have formulated a general method of calculation of the truly non-perturbative Yang-Mills vacuum energy density (this is, by definition, the Bag constant apart from the sign). It is the main dynamical characteristic of the QCD ground state. Our method allows one to make it free of the perturbative contributions ('contaminations'), by construction. We also perform an actual numerical calculation of the Bag constant for the confining effective charge. Its choice uniquely defines the Bag constant, which becomes free of all the types of the perturbative contributions now, as well as possessing many other desirable properties as colorless, gauge independence, etc. Using further the trace anomaly relation, we develop a general formalism which makes it possible to relate the Bag constant to the gluon condensate not using the weak coupling solution for the corresponding $\beta$ function. Our numerical result for the Bag constant shows a good agreement with other phenomenological estimates of the gluon condensate.Comment: 28 pages and 4 figures, typos corrected, added new appendices and new references in comparison with the published versio

Standard Model CP-violation and Baryon asymmetry

Simply based on CP arguments, we argue against a Standard Model explanation of the baryon asymmetry of the universe in the presence of a first order phase transition. A CP-asymmetry is found in the reflection coefficients of quarks hitting the phase boundary created during the electroweak transition. The problem is analyzed both in an academic zero temperature case and in the realistic finite temperature one. The building blocks are similar in both cases: Kobayashi-Maskawa CP-violation, CP-even phases in the reflection coefficients of quarks, and physical transitions due to fermion self-energies. In both cases an effect is present at order $\alpha_W^2$ in rate. A standard GIM behaviour is found as intuitively expected. In the finite temperature case, a crucial role is played by the damping rate of quasi-particles in a hot plasma, which is a relevant scale together with $M_W$ and the temperature. The effect is many orders of magnitude below what observation requires, and indicates that non standard physics is indeed needed in the cosmological scenario.Comment: 15p, LaTeX (3figs incl.), CERN 93/7081,LPTHE Orsay-93/48,HUTP-93/A036,HD-THEP-93-4

Standard Model CP-violation and Baryon asymmetry Part II: Finite Temperature

We consider the scattering of quasi-particles off the boundary created during a first order electroweak phase transition. Spatial coherence is lost due to the quasi-quark damping rate, and we show that reflection on the boundary is suppressed, even at tree-level. Simply on CP considerations, we argue against electroweak baryogenesis in the Standard Model via the charge transport mechanism. A CP asymmetry is produced in the reflection properties of quarks and antiquarks hitting the phase boundary. An effect is present at order $\alpha_W^2$ in rate and a regular GIM behaviour is found, which can be expressed in terms of two unitarity triangles. A crucial role is played by the damping rate of quasi-particles in a hot plasma, which is a relevant scale together with $M_W$ and the temperature. The effect is many orders of magnitude below what observation requires.Comment: 44 pages, CERN-TH.7263/94, LPTHE Orsay-94/49, HUTP-94/A015, HD-THEP-94-20, FTUAM-94/14, NSF-ITP-94-6

Surface and gene expression of immunoglobulin E receptors on mast cells and mast-cell numbers in interleukin-4-gene knockout mice

We quantified immunoglobulin E (IgE) on peritoneal mast cells of interleukin-4 (IL-4)-gene knockout (−/−) mice and wild-type (+/+) controls using a cytofluorometric method, and examined the expression of IgE receptors, estimated by quantifying the total binding of IgE on the mast cells of IL-4 (−/−) mice. The mast cells of IL-4 (+/+) mice, identified and measured using microscope fluorometry, had a fluorescence intensity five to six times higher than that of non-mast cells, while the mast cells obtained from IL-4 (−/−) mice had fluorescence intensities within the range of those of non-mast cells. Two weeks after an infection with Nippostrongylus brasiliensis, the fluorescence intensity of the mast cells of IL-4 (+/+) mice increased to a level about twice as high as that before immunization. However, no significant increase after infection was observed in IL-4 (−/−) mice. Furthermore, the mast cells of IL-4 (−/−) mice did not bind IgE when incubated with IgE at concentrations that saturated IgE receptors on the mast cells of wild-type controls, thereby indicating that the expression of IgE receptors on mast cells was impaired in the IL-4-deficient mice. Using a reverse transcription–polymerase chain reaction, we found gene expression of all three subunits (α-, β- and γ-chains) of the IgE receptor in IL-4 (−/−) like that in IL-4 (+/+) mice. The results thus suggest that the binding of IgE may be essential to induce the translation of mRNA to IgE-receptor proteins. We also observed that there were about twice as many peritoneal mast cells in the IL-4 (−/−) mice as there were in the IL-4 (+/+) mice, in both immunized and non-immunized animals. This was unexpected in view of previous findings suggesting that IL-4, in concert with stem cell factor and IL-3, stimulates the proliferation and differentiation of mast cells in vitro

The relationship between dividend policy, financial structure, profitability and firm value

This paper investigates the value creation process in the Tunisia stock exchange using a sample including more than 90% of the listed companies. In order to find out the determinants of the value creation of the selected companies, it uses the random probit model estimation procedure with unbalanced panel data. The results indicate that the probability of creating future values is positively and significantly correlated with profitability factor. In addition, the results also suggest that the value creation is affected by industry patterns (listed banks are the more value creator in the Tunisia stock exchange), by size (the probability to create value is stronger in small firms than in big ones) and by nature of property (the probability to create value is stronger in private-owned firms than in public-owned ones). Last but not least, the time trend factor is positive and highly significant. This finding suggests that the progressive reforms of the Tunisian stock exchange have attracted new investors, who have contributed by their purchase to the appreciation of the value of listed shares.

APE computers--past, present and future

International audienc