5,128 research outputs found
Bounds on from 3-3-1 model at the LHC energies
The Large Hadron Collider will restart with higher energy and luminosity in
2015. This achievement opens the possibility of discovering new phenomena
hardly described by the Standard Model, that is based on two neutral gauge
bosons: the photon and the . This perspective imposes a deep and systematic
study of models that predicts the existence of new neutral gauge bosons. One of
such models is based on the gauge group
called 3-3-1 model for short.
In this paper we perform a study with predicted in two versions of
the 3-3-1 model and compare the signature of this resonance in each model
version. By considering the present and future LHC energy regimes, we obtain
some distributions and the total cross section for the process . Additionally, we derive lower bounds
on mass from the latest LHC results. Finally we analyze the LHC
potential for discovering this neutral gauge boson at 14 TeV center-of-mass
energy.Comment: 6 pages, 9 figures, 2 table
Cosmic String in Scalar-Tensor Gravity
The gravitational properties of a local cosmic string in the framework of
scalar-tensor gravity are examined. We find the metric in the weak-field
approximation and we show that, contrary to the General Relativity case, the
cosmic string in scalar-tensor gravitation exerces a force on non-relativistic,
neutral test particle. This force is proportional to the derivative of the
conformal factor and it is always attractive. Moreover, this
force could have played an important role at the Early Universe, although
nowadays it can be neglegible. It is also shown that the angular separation
remains unaltered for scalar-tensor cosmic strings.Comment: 15 pages, LATEX, no figure
Caprinocultura e ovinocultura: crescimento promissor x desorganização preocupante.
bitstream/item/52348/1/Midia-Caprinocultura-e-ovinocultura.pd
Comparison of 120Sn(6He,6He)120Sn and 120Sn(alpha,alpha)120Sn elastic scattering and signatures of the 6He neutron halo in the optical potential
Cross sections of Sn(,)Sn elastic scattering
have been extracted from the particle beam contamination of a recent
Sn(He,He)Sn experiment. Both reactions are analyzed
using systematic double folding potentials in the real part and smoothly
varying Woods-Saxon potentials in the imaginary part. The potential extracted
from the Sn(He,He)Sn data may be used as the basis for
the construction of a simple global He optical potential. The comparison of
the He and data shows that the halo nature of the He nucleus
leads to a clear signature in the reflexion coefficients : the relevant
angular momenta with and are shifted to
larger with a broader distribution. This signature is not present in the
scattering data and can thus be used as a new criterion for the
definition of a halo nucleus.Comment: 13 pages, 7 figures, accepted for publication in Phys. Rev.
Massive scalar field near a cosmic string
The function of a massive scalar field near a cosmic string is
computed and then employed to find the vacuum fluctuation of the field. The
vacuum expectation value of the energy-momentum tensor is also computed using a
point-splitting approach. The obtained results could be useful also for the
case of self-interacting scalar fields and for the finite-temperature Rindler
space theory.Comment: 15 pages, standard LaTeX, no figures. Reference [14] correcte
Sistema Agrossilvipastoril caprinos e ovinos: reunião técnica.
bitstream/item/29833/1/DOC-97.pd
Cerebellar ataxia with spasmodic cough: a new form of dominant ataxia
Background: Although mentioned in most series, “pure”
autosomal dominant cerebellar ataxias, except spinocerebellar
ataxia type 6, are difficult to differentiate on clinical
grounds.
Objective: To describe Portuguese families with a peculiar
pure form of dominant ataxia that, to our knowledge,
has never been documented before and in which
cerebellar signs are preceded by spasmodic cough.
Patients: Through a population-based survey of hereditary
ataxias in Portugal, we identified 19 patients in
6 families with this particular disorder.
Results: The majority of patients had a pure late-onset
ataxia with a benign evolution. In all of the families, attacks
of spasmodic coughing preceded ataxia for 1 to 3
decades and were a reliable marker of the disease. In Portugal,
this form of ataxia accounts for 2.7% of all of the
dominant ataxias.
Conclusions: The families that we describe shared
some relevant clinical and imagiological features with
spinocerebellar ataxia type 5 and the recently described
spinocerebellar ataxia type 20, allelic to spinocerebellar
ataxia type 5. Spinocerebellar ataxia types 5 and 20
could be different phenotypic expressions of the same
molecular disorder. The association of a dominant
ataxia with spasmodic cough is rare but probably underdiagnosed.Fundação para a Ciência e Tecnologi
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