4,830 research outputs found
Sterile neutrino dark matter, CDMS-II and a light Higgs boson
We add a singlet right handed neutrino plus a charged and a neutral singlet
scalars to the standard model. This extension includes a discrete symmetry such
that we obtain a heavy sterile neutrino which couples only to the electron and
the new scalars. In this sense the singlet neutrino does not mix with ordinary
ones and thus has no effect on Big Bang Nucleosynthesis. However, such sterile
neutrino can be in equilibrium with electroweak particles in the early Universe
due to its couplings to electrons and also because the Higgs boson mixes with
the singlet scalars. We obtain that the sterile neutrino constitutes a dark
matter candidate and analyze its direct detection in the light of current
experiments. Our results show that if such a sterile neutrino is realized in
nature, and CDMS-II experiment confirms its positive signal, dark matter
demands a rather light Higgs boson with new Physics at some 500 GeV scale.Comment: 16 pages, 13 figures, uses axodraw.st
A 331 WIMPy Dark Radiation Model
Recent observations suggest that the number of relativistic degrees of
freedom in the early universe might exceed what is predicted in the standard
cosmological model. If even a small, percent-level fraction of dark matter
particles are produced relativistically, they could mimic the effect of an
extra realistic species at matter-radiation equality while obeying BBN, CMB and
Structure Formation bounds. We show that this scenario is quite naturally
realized with a weak-scale dark matter particle and a high-scale ``mother''
particle within a well motivated 3-3-1 gauge model, which is particularly
interesting for being consistent with electroweak precision measurements, with
recent LHC results, and for offering a convincing explanation for the number of
generations in the Standard Model.Comment: 10 pages,7 figures. Matches Published EPJC versio
Explaining ATLAS and CMS Results Within the Reduced Minimal 3-3-1 model
Recently the ATLAS and CMS collaborations announced the discovery of a higgs
particle with a mass of GeV. The results are mildly consistent with
the Standard Model Higgs boson. However, the combined data from these
collaborations seem to point to an excess in the
channel. In this work we analyze under which conditions this excess may be
plausibly explained within the reduced minimal 3-3-1 model, while being
consistent with bb, WW, ZZ and channels. Moreover, we derive the
properties of the heavy neutral and the doubly charged scalars predicted by the
model. We then conclude that at a scale of a few TeV, this model provides a
good fit to the ATLAS and CMS signal strength measurements, and therefore
stands as an appealing alternative to the standard model.Comment: 23 pages, 9 figures. References adde
Generalized Differential Geometry
Generalized Functions play a central role in the understanding of
differential equations containing singularities and nonlinearities. Introducing
infinitesimals and infinities to deal with these obstructions leads to
controversies concerning the existence, rigor and the amount of non-standard
analysis needed to understand these theories. Milieus constructed over the
generalized reals sidestep them all. A Riemannian manifold M embeds discretely
into a generalized manifold on which singularities vanish and products of
nonlinearities make sense. Linking this to an already existing global theory
provides an algebra embedding . Generalized Space-Time is
constructed and its possible effects on Classical Space-Time are examined
Estudo histopatológico das lesões causadas pelo veneno de urutu (Bothrops alternatus) em músculo esquelético de camundongos
Veneno bruto de urutu (Bothrops alternatus) dissolvido em solução salina fisiológica foi injetado no músculo tibial anterior direito de camundongos adultos na dose de 80 μg. Os músculos foram examinados em cortes de parafina, corados por Hematoxilina e Eosina. Aos 10 minutos já havia intensa hemorragia difusa no M. tibial anterior, mas apenas raras fibras musculares estavam necróticas. Nas horas seguintes, contudo, observou-se rápido aumento do número de fibras afetadas, sendo que à s 24 hs o músculo apresentava-se totalmente necrótico. Vasos sangüÃneos intramusculares e nas proximidades do M. tibial anterior mostravam necrose hialina da camada média e por vezes trombose. A fagocitose dos restos celulares ocorreu da periferia para o centro e acompanhou-se de regeneração muscular. Após 1 a 2 meses, em vários animais houve recuperação considerável do músculo, embora com persistência de cicatriz. As fibras regeneradas possuiam núcleos centrais e variavam em diâmetro, estando muitas atróficas. Em outros camundongos a regeneração do M. tibial anterior foi muito precária, tendo este sido substituÃdo por tecido fibroadiposo com apenas raras fibras musculares. Os resultados mostram que, apesar da gravidade das lesões iniciais devidas ao veneno, ocorre regeneração muscular em grau variável de animal para animal. Sugere-se que a má regeneração observada em alguns casos poderia ser devida, ao menos em parte, a dano vascular permanente.Venom of urutu snake (Bothrops alternatus) injected into the Tibialis anterior muscle (Tib. ant.) of mice in a dose of 80 μg induced massive local haemorrhage within 10 min. Though muscle fibres appeared normal at this stage they later suffered necrosis in increasing numbers so that by 24 hr the whole muscle was necrotic. Arteries near the injection site often showed hyaline necrosis of the media and some were thrombosed. Phagocytosis of debris, which progressed from the periphery towards the centre of the necrotic area was usually complete by 2 weeks and was accompanied by muscle fibre regeneration. After 1 or 2 months several animals showed extensive recovery of the damaged muscle though a localized scar often remained. The regenerated muscle fibres showed central nuclei and varied in diameter, many appearing atrophic. In other mice, however, there was replacement of Tib. ant. by fibroadipose tissue with little or no muscle fibre regeneration. The results show that despite severe initial haemorrhage and necrosis, the affected muscles exhibit considerable capacity for regeneration. It is suggested that the poor regenerative response observed in some animals could result, at least to some extent, from permanent damage to the local blood vessels
Solving 1ODEs with functions
Here we present a new approach to deal with first order ordinary differential
equations (1ODEs), presenting functions. This method is an alternative to the
one we have presented in [1]. In [2], we have establish the theoretical
background to deal, in the extended Prelle-Singer approach context, with
systems of 1ODEs. In this present paper, we will apply these results in order
to produce a method that is more efficient in a great number of cases.
Directly, the solving of 1ODEs is applicable to any problem presenting
parameters to which the rate of change is related to the parameter itself.
Apart from that, the solving of 1ODEs can be a part of larger mathematical
processes vital to dealing with many problems.Comment: 31 page
On the connection of Gamma-rays, Dark Matter and Higgs searches at LHC
Motivated by the upcoming Higgs analyzes we investigate the importance of the
complementarity of the Higgs boson chase on the low mass WIMP search in direct
detection experiments and the gamma-ray emission from the Galactic Center
measured by the Fermi-LAT telescope in the context of the . We obtain the relic abundance, thermal cross section,
the WIMP-nucleon cross section in the low mass regime and network them with the
branching ratios of the Higgs boson in the model. We conclude that the Higgs
boson search has a profound connection to the dark matter problem in our model,
in particular for the case that ( GeV) the BR(
WIMPs) . This scenario could explain this plateau of any mild
excess regarding the Higgs search as well as explain the gamma-ray emission
from the galactic center through the channel with a WIMP in the mass
range of 25-45 GeV, while still being consistent with the current limits from
XENON100 and CDMSII. However, if the recent modest excesses measured at LHC and
TEVATRON are confirmed and consistent with a standard model Higgs boson this
would imply that GeV, consequently ruling out any attempt to
explain the Fermi-LAT observations.Comment: 8 pages, 9 figure
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