10,651 research outputs found
Explicitly broken lepton number at low energy in the Higgs triplet model
We suppose that lepton number is explicitly broken at low energy scale(M) in
the framework of the Higgs triplet() model. The scalar sector of the
model is developed considering the particular assumption
eV. We show that such assumption infers a particular mass spectrum for the
scalars that compose the triplet and cause a decoupling of these scalars from
those that compose the standard scalar doublet.Comment: Minor changes, New references added, To appear at MPL
Asymptotic stability at infinity for differentiable vector fields of the plane
Let X:R2\Dr->R2 be a differentiable (but not necessarily C1) vector field,
where r>0 and Dr={z\in R2:|z|\le r}. If for some e>0 and for all p\in R2\Dr, no
eigenvalue of D_p X belongs to (-e,0]\cup {z\in\C:\mathcal{R}(z)\ge 0}, then
(a)For all p\in R2\Dr, there is a unique positive semi--trajectory of X
starting at p; (b)\mathcal{I}(X), the index of X at infinity, is a well defined
number of the extended real line [-\infty,\infty); (c) There exists a constant
vector v\in R2 such that if \mathcal{I}(X) is less than zero (resp. greater or
equal to zero), then the point at infinity \infty of the Riemann sphere
R2\cup\set{\infty} is a repellor (resp. an attractor) of the vector field X+v.Comment: 16 pages, 7 figure
Neutrinoless double beta decay with and without Majoron-like boson emission in a 3-3-1 model
We consider the contributions to the neutrinoless double beta decays in a
electroweak model. We show that for a range of the
parameters in the model there are diagrams involving vector-vector-scalar and
trilinear scalar couplings which can be potentially as contributing as the
light massive Majorana neutrino exchange one. We use these contributions to
obtain constraints upon some mass scales of the model, like the masses of the
new charged vector and scalar bosons. We also consider briefly the decay in
which besides the two electrons a Majoron-like boson is emitted.Comment: Revtex, 10 pages and 8 eps figures. Extended version to be published
in Physical Review
Developing frameworks for protocol implementation
This paper presents a method to develop frameworks for protocol implementation. Frameworks are software structures developed for a specific application domain, which can be reused in the implementation of various different concrete systems in this domain. The use of frameworks support a protocol implementation process connected with formal design methods and produce an implementation code easy to extend and to reuse
Li-Yorke Chaos for Composition Operators on -Spaces
Li-Yorke chaos is a popular and well-studied notion of chaos. Several simple
and useful characterizations of this notion of chaos in the setting of linear
dynamics were obtained recently. In this note we show that even simpler and
more useful characterizations of Li-Yorke chaos can be given in the special
setting of composition operators on spaces. As a consequence we obtain a
simple characterization of weighted shifts which are Li-Yorke chaotic. We give
numerous examples to show that our results are sharp
Criar Ciência
Antes de desenvolver o tema ―Criar ciência‖, propriamente
dito, sinto a necessidade de definir alguns termos e de enquadrar
alguns conceitos. Em primeiro lugar, este capÃtulo dedica-se à s
Ciências ditas Exatas e Naturais, sejam elas de caráter
fundamental ou aplicado, podendo provavelmente grande parte do
que aqui está escrito aplicar-se igualmente à Tecnologia. No
entanto, será que os processos e conceitos ligados à criação da
Ciência nestas áreas do conhecimento diferem dos que regem as
Ciências Humanas e Sociais? Provavelmente não, mas cabe ao
leitor responder a esta pergunta através dos textos aqui
apresentados. Em segundo lugar, as próprias Ciências ditas Exatas
e Naturais abrangem mundos tão diversos e distintos, tanto no que
diz respeito às escalas abrangidas (espaciais ou temporais), como
ao seu próprio estado de desenvolvimento, pelo que me é
obviamente impossÃvel abordar estas ciências no seu conjunto.
Com estas palavras exemplifico perfeitamente, o dilema da maior
parte dos cientistas: Como falar de um tema sabendo
perfeitamente que o que se irá dizer, só se verifica para alguns
casos especÃficos ou até mesmo para uma grande maioria, mas
nunca para tudo e todos
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