Theta Term in QCD sum rules at Finite Temperature and the Neutron Electric Dipole Moment

By using thermal QCD sum rules to investigate the $\bar{\theta}$ induced neutron electric dipole moment $d_n$, we have examined the behaviour of broken CP symmetry at finite temperature. We find that, below the critical temperature, the ratio $\mid {d_n \over \bar{\theta}}\mid$ slightly decreases but survives at temperature effects, implying T nonrestoration of CP-invariance \cite{Chabab}.Comment: 08pages, Latex, Invited Tall given at the Second International Workshop on Hadron Physics, Effective Theories of Low Energy QCD, 25-29 September, 2002 (Coimbra, Portugal); to appear in the proceeding

Confining interquark potentials from nonabelian gauge theories coupled to dilaton

Following a recently proposed confinement generating mechanism, we provide a new string inspired model with a massive dilaton and a new dilaton coupling function [5]. By solving analytically the equations of motion, a new class of confining interquark potentials is derived which includes several popular potential forms given in the literature.Comment: 7 pages, based on hep-th/0311096. Presented at 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4 Sep 200

Strong CP problem, Neutron EDM and Thermal QCD sum rules

The behaviour of the broken CP symmetry at finite temperature is examined. This is achieved through the investigation of the neutron electric dipole moment $d_n$ induced by $\theta$-term. By using thermal QCD sum rules, we find that below the critical temperature, the ratio $\mid {d_n \over \bar{\theta}}\mid$ slightly decreases but survives at temperature effects. This evolution implies that CP remains broken at finite temperature as required by Baryogenesis \cite{Chabab}.Comment: 08 pages. Contributed to Hadron 03: 10th International Conference on Hadron Spectroscopy, Aschaffenburg, Germany, 31 Aug - 6 Sep 200

Confinement Driven by Scalar Field in 4d Non Abelian Gauge Theories

We review some of the most recent work on confinement in 4d gauge theories with a massive scalar field (dilaton). Emphasis is put on the derivation of confining analytical solutions to the Coulomb problem versus dilaton effective couplings to gauge terms. It is shown that these effective theories can be relevant to model quark confinement and may shed some light on confinement mechanism. Moreover, the study in the heavy meson sector of an interquark potential derived from Dick Model, proves that phenomenological investigation of this mechanism is more than justified and deserves more efforts.Comment: 8 pages, Talk given at Cairo International Conference on High Energy Physics (CICHEP II), January 14-17, 2006, Cairo, Egyp