We use the method of thermal QCD sum rules to investigate the effects of temperature on the neutron electric dipole moment d n induced by the vacuumθ-angle. Then, we analyze and discuss the thermal behaviour of the ratio | dn θ | in connection with the restoration of the CP-invariance at finite temperature. *

We extend the Vecchia-Veneziano-Witten (VVW) model of QCD in the chiral limit and for large colour number N c , by introducing an effective dilaton-gluon coupling from which we derive both the axion and dilaton potentials. Furthermore, using a string inspired model, we determine a new interquark potential as a perturbative series in terms of the interquark distance r. Our potential goes beyond Dick one obtained in [8] and shares the same features as the Bian-Huang-Shen potential V BHS which depends only on odd powers of r [22]. * mchabab@ucam.ac.ma

No abstract

In particle physics and cosmology, the dilaton is an hypothetical scalar field which can explain many physical phenomena. In this framework, we investigate an extended lagrangian of QCD which involves dilatonic degrees of freedom. Our approach is based on the relationship between the massive dilaton and the nonperturbative effects of QCD. We derive a general axion potential involving the dilaton properties and vacuum condensates. * n.elbiaze@uiz.ac.ma

The scalar field plays an fundamental role in the investigation of confinement property characterising many particle physics models. This is achieved by coupling this particle directly with gauge fields at the lagrangian level. We have adopted the same approach to determine a potential [10] as a perturbative series in terms of interquark distance. In order to introduce the gravitational effects and inspired from bag models, we implement a scalar field which interacts both with the vacuum and the electron field. In this context and with presence of the vacuum condensates, it is possible to derive a more accurate expression of the electron energy.