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

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

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

CP violation in Charged Higgs Bosons decays H±→W±(γ,Z)H^\pm \to W^\pm (\gamma, Z) in the Minimal Supersymmetric Standard Model (MSSM)

One loop mediated charged Higgs bosons decays $H^\pm\to W^\pm V$, $V= Z, \gamma$ are studied in the Minimal Supersymmetric Standard Model (MSSM) with and without CP violating phases. We evaluate the MSSM contributions to these processes taking into account $B\to X_s\gamma$ constraint as well as experimental constraints on the MSSM parameters. In the MSSM, we found that in the intermediate range of \tan\beta \la 10 and for large A_t and large $\mu$, where the lightest top squark becomes very light and hence non-decoupled, the branching ratio of $H^\pm \to W^{\pm} Z$ can be of the order 10^{-3} while the branching ratio of $H^\pm \to W^{\pm} \gamma$ is of the order 10^{-5}. We found also that the CP violating phases of soft SUSY parameters can modify the branching ratio by about one order of magnitude. We also show that MSSM with CP violating phases lead to CP-violating asymmetry in the decays $H^+ \to W^+V$ and $H^- \to W^-V$. Such CP asymmetry can be rather large and can reach 80% in some region of parameter space.Comment: Invited talk at CTP Symposium on Supersymmetry at LHC: Theoretical and Experimental Prospectives, Cario, Egypt, 11-14 Mar 200