C. Hamzaoui

Higgs-boson-mediated FCNC in supersymmetric models with large tan(beta)

In the supersymmetric models with nontrivial flavour structure in the soft-breaking sector the exchange of neutral Higgses mediates ΔF=2 transitions. This mechanism is studied for ΔS,ΔB=2 processes and for a generic form of the soft-breaking terms. We find that Higgs-mediated FCNC amplitudes increase very rapidly with tanβ and can exceed SUSY box contribution by up to two orders of magnitude when tanβ∼mt/mb.

Flavor-changing top quark decay within the minimal supersymmetric standard model

We present the results of the gluino and scalar quark contribution to the flavor-changing top quark decay into a charm quark and a photon, gluon, or a {ital Z}{sup 0} boson within the minimal supersymmetric standard model. We include the mixing of the scalar partners of the left- and right-handed top quark. This mixing has several effects, the most important of which is to greatly enhance the {ital c} {ital Z} decay mode for large values of the soft SUSY-breaking scalar mass {ital m}{sub {ital S}} and to give rise to a GIM-like suppressions in the {ital c} {gamma} mode for certain combinations of parameters.

Limits on CP-odd four-fermion operators containing the strange quark field

The bounds on the neutron electric dipole moment and {ital T}-odd nucleon-nucleon interaction are used to extract the limits on the effective CP-odd four-fermion operators containing a strange quark field. This completes the study of the dim=5,6 CP-odd operators built from light-quark fields. The limits are very strong and comparable to those obtained previously for operators containing up and down flavors. We also analyze the shift of the axionic vacuum, {theta}{sub eff}, induced by four-fermion operators in the presence of the PQ mechanism and conclude that this gives subleading contributions to CP-odd observables as compared with the direct ones. {copyright} {ital 1999} {ital The American Physical Society}

Constrained MSSM and the electric dipole moment of the neutron

We study the constraints on the CP-violating soft-breaking phases in the minimal supersymmetric standard model using the limits on the chromoelectric dipole moment of the strange quark extracted from the neutron EDM experiment. Our investigation shows that the phase mediated by the gluino exchange diagram has to be very small,

Neutrino mass textures and partial mu-tau symmetry

phileq 8 10^{-4}

Electric dipole moment of the neutron in the Kobayashi-Maskawa model with four generations of quarks

, for the common supersymmetric mass of the order of 100 GeV. Then, solving the renormalization group equations analytically by iterations, we calculate the electric dipole moment of the neutron in the MSSM with CP-conserving soft-breaking parameters for the case of three and four generations. For the three-generation case we resolve the apparent discrepancies between order-of-magnitude estimates and numerical calculations existing in the literature. In this case the EDM of the neutron does not exceed

Neutrino mixing and leptogenesis in mu-tau symmetry

10^{-32} e cm

Rotated

. For the four-generation case we show that there is a significant enhancement which renders the EDM of the neutron at a measurable level of

\mu - \tau

10^{-26}e cm

symmetry for one generic neutrino mixing angle: An analytical study

.