542 research outputs found
Theta Term in QCD sum rules at Finite Temperature and the Neutron Electric Dipole Moment
By using thermal QCD sum rules to investigate the induced
neutron electric dipole moment , we have examined the behaviour of broken
CP symmetry at finite temperature. We find that, below the critical
temperature, the ratio 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
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 induced by -term.
By using thermal QCD sum rules, we find that below the critical temperature,
the ratio 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
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
On the implications of a dilaton in gauge theory
Some recent work on the implications of a dilaton in 4d gauge theories are
revisited. In part I of this paper we see how an effective dilaton coupling to
gauge kinetic term provides a simple attractive mechanism to generate
confinement. In particular, we put emphasis on the derivation of confining
analytical solutions and look into the problem how dilaton degrees of freedom
modify Coulom potential and when a confining phase occurs. In part II, we solve
the semi-relativistic wave equation, for Dick interquark potential using the
Shifted l-expansion technique (SLET) in the heavy quarkonium sector. The
results of this phenomenological analysis proves that these effective theories
can be relevant to model quark confinement and may shed some light on
confinement mechanism.Comment: 8 pages. Talk given at CTP Symposium on Supersymmetry at LHC:
Theoretical and Experimental Prospectives, Cairo, Egypt, 11-14 Mar 200
Bohr Hamiltonian with Hulth?en plus Ring shaped potential for triaxial nuclei
In this paper, we solve the eigenvalues and eigenvectors problem with Bohr
collective Hamil- tonian for triaxial nuclei. The ? beta part of the collective
potential is taken to be equal to Hulth?en potential while the gamma part is
defined by a new generalized potential obtained from a ring shaped one.
Analytical expressions for spectra and wave functions are derived by means of a
recent version of the asymptotic iteration method and the usual approximations.
The calculated energies and B(E2) transition rates are compared with
experimental data and the available theoretical results in the literature.Comment: 14 pages, 4 tables, 9 figures, accepted to be published in epj
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