45,856 research outputs found
Realizing the supersymmetric inverse seesaw model in the framework of R-parity violation
If, on one hand, the inverse seesaw is the paradigm of TeV scale seesaw
mechanism, on the other it is a challenge to find scenarios capable of
realizing it. In this work we propose a scenario, based on the framework of
R-parity violation, that realizes minimally the supersymmetric inverse seesaw
mechanism. In it the energy scale parameters involved in the mechanism are
recognized as the vacuum expectation values of the scalars that compose the
singlet superfields and . We develop also the scalar sector
of the model and show that the Higgs mass receives a new tree-level
contribution that, when combined with the standard contribution plus loop
correction, is capable of attaining GeV without resort to heavy stops.Comment: Minor modification of the text. Final version to be published in PL
Spiralling dynamics near heteroclinic networks
There are few explicit examples in the literature of vector fields exhibiting
complex dynamics that may be proved analytically. We construct explicitly a
{two parameter family of vector fields} on the three-dimensional sphere
\EU^3, whose flow has a spiralling attractor containing the following: two
hyperbolic equilibria, heteroclinic trajectories connecting them {transversely}
and a non-trivial hyperbolic, invariant and transitive set. The spiralling set
unfolds a heteroclinic network between two symmetric saddle-foci and contains a
sequence of topological horseshoes semiconjugate to full shifts over an
alphabet with more and more symbols, {coexisting with Newhouse phenonema}. The
vector field is the restriction to \EU^3 of a polynomial vector field in
\RR^4. In this article, we also identify global bifurcations that induce
chaotic dynamics of different types.Comment: change in one figur
Sensitivity Analysis for a Scenario-Based Reliability Prediction Model
As a popular means for capturing behavioural requirements, scenariosshow how components interact to provide system-level functionality.If component reliability information is available, scenarioscan be used to perform early system reliability assessment. Inprevious work we presented an automated approach for predictingsoftware system reliability that extends a scenario specificationto model (1) the probability of component failure, and (2) scenariotransition probabilities. Probabilistic behaviour models ofthe system are then synthesized from the extended scenario specification.From the system behaviour model, reliability predictioncan be computed. This paper complements our previous work andpresents a sensitivity analysis that supports reasoning about howcomponent reliability and usage profiles impact on the overall systemreliability. For this purpose, we present how the system reliabilityvaries as a function of the components reliabilities and thescenario transition probabilities. Taking into account the concurrentnature of component-based software systems, we also analysethe effect of implied scenarios prevention into the sensitivity analysisof our reliability prediction technique
A family of rotation numbers for discrete random dynamics on the circle
We revisit the problem of well-defining rotation numbers for discrete random
dynamical systems on the circle. We show that, contrasting with deterministic
systems, the topological (i.e. based on Poincar\'{e} lifts) approach does
depend on the choice of lifts (e.g. continuously for nonatomic randomness).
Furthermore, the winding orbit rotation number does not agree with the
topological rotation number. Existence and conversion formulae between these
distinct numbers are presented. Finally, we prove a sampling in time theorem
which recover the rotation number of continuous Stratonovich stochastic
dynamical systems on out of its time discretisation of the flow.Comment: 15 page
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