4,870 research outputs found
Moduli Stabilization in Type IIB Flux Compactifications
In the present paper, we reexamine the moduli stabilization problem of the
Type IIB orientifolds with one complex structure modulus in a modified two-step
procedure. The full superpotential including both the 3-form fluxes and the
non-perturbative corrections is used to yield a F-term potential. This
potential is simplified by using one optimization condition to integrate the
dilaton field out. It is shown that having a locally stable supersymmetric
Anti-deSitter vacuum is not inevitable for these orientifolds, which depend
strongly upon the details of the flux parameters. For those orientifolds that
have stable/metastable supersymmetry-broken minima of the F-term potential, the
deSitter vacua might emerge even without the inclusion of the uplifting
contributions.Comment: 10 pages, LaTeX2e style. The paper is rewritten in ver3 with more
references adde
Top-Quark FCNC Decay t->cgg in Topcolor-assisted Technicolor Model
The topcolor-assisted technicolor (TC2) model predicts several pseudo-scalars
called top-pions and at loop level they can induce the FCNC top quark decay
t->cgg which is extremely suppressed in the Standard Model (SM). We find that
in the allowed parameter space the TC2 model can greatly enhance such a FCNC
decay and push the branching ratio up to 10^{-3}, which is much larger than the
predictions in the SM (10^{-9}) and in the minimal supersymmetric model
(10^{-4}). We also compare the result with the two-body FCNC decay t-> cg and
find that the branching ratio of t-> cgg is slightly larger than t-> cg. Such
enhanced FCNC top quark decays may serve as a good probe of TC2 model at the
future top quark factory.Comment: 11 pages, 4 figure
- …