17,155 research outputs found
Lepton Flavor Violation and Collider Searches in a Type I + II Seesaw Model
Neutrino are massless in the Standard Model. The most popular mechanism to
generate neutrino masses are the type I and type II seesaw, where right-handed
neutrinos and a scalar triplet are augmented to the Standard Model,
respectively. In this work, we discuss a model where a type I + II seesaw
mechanism naturally arises via spontaneous symmetry breaking of an enlarged
gauge group. Lepton flavor violation is a common feature in such setup and for
this reason, we compute the model contribution to the
and decays. Moreover, we explore the connection between
the neutrino mass ordering and lepton flavor violation in perspective with the
LHC, HL-LHC and HE-LHC sensitivities to the doubly charged scalar stemming from
the Higgs triplet. Our results explicitly show the importance of searching for
signs of lepton flavor violation in collider and muon decays. The conclusion
about which probe yields stronger bounds depends strongly on the mass ordering
adopted, the absolute neutrino masses and which much decay one considers. In
the 1-5 TeV mass region of the doubly charged scalar, lepton flavor violation
experiments and colliders offer orthogonal and complementary probes. Thus if a
signal is observed in one of the two new physics searches, the other will be
able to assess whether it stems from a seesaw framework.Comment: 41 pages, 1 figure, 2 table
Association of mid-infrared solar plages with Calcium K line emissions and magnetic structures
Solar mid-IR observations in the 8-15 micrometer band continuum with moderate
angular resolution (18 arcseconds) reveal the presence of bright structures
surrounding sunspots. These plage-like features present good association with
calcium CaII K1v plages and active region magnetograms. We describe a new
optical setup with reflecting mirrors to produce solar images on the focal
plane array of uncooled bolometers of a commercial camera preceded by germanium
optics. First observations of a sunspot on September 11, 2006 show a mid-IR
continuum plage exhibiting spatial distribution closely associated with CaII
K1v line plage and magnetogram structures. The mid-IR continuum bright plage is
about 140 K hotter than the neighboring photospheric regions, consistent with
hot plasma confined by the magnetic spatial structures in and above the active
regionComment: 5 pages, 4 figures. Accepted by PAS
Exactly Solvable Models of Interacting Spin-s Particles in one-dimension
We consider the exact solution of a many-body problem of spin- particles
interacting through an arbitrary U(1) invariant factorizable -matrix. The
solution is based on a unified formulation of the quantum inverse scattering
method for an arbitrary -dimensional monodromy matrix. The respective
eigenstates are shown to be given in terms of creation fields by a general
new recurrence relation. This allows us to derive the spectrum and the
respective Bethe ansatz equations.Comment: 10 pages, plain late
Controle Biológico de traça-da-cera com Bacillus thuringiensis para a conservação de favos na apicultura sustentável e agricultura familiar.
As abelhas melíferas efetuam numerosas e importantes atividades que favorecem a humanidade e, na agricultura familiar, contribuem para a sustentabilidade de sistemas de produção de base ecológica, favorecendo a polinização dos cultivos, a produção de mel, pólen e própolis para alimentação da família e a geração de novas fontes de renda. Na apicultura, a conservação dos favos contra o risco de ataque e destruição pelas traças-da-cera é assunto de interesse econômico e motivação de uma série de estratégias pelos apicultores. Com o objetivo de avaliar a possibilidade de uso de formulações comerciais de Bacillus thuringiensis como agente biológico de conservação natural de favos de cera de abelhas melíferas, foi testada a mortalidade de lagartas de Galleria mellonella a diferentes concentrações de B. thuringiensis e verificado o impacto destas concentrações sobre Apis mellifera africanizadas em fase larval. Testes foram conduzidos em laboratório com lagartas de G. mellonella e a campo com larvas de A. mellifera africanizadas, em delineamentos completamente casualizados, com seis tratamentos e quatro repetições, em concentrações próximas da dose de campo recomendada para o produto comercial à base de B. thuringiensis. Concluiu-se que a aplicação de B. thuringiensis nas maiores concentrações utilizadas apresenta efeito favorável ao controle de G. mellonella quando os favos são imersos no produto e que, porém, as mesmas concentrações apresentam efeito direto significativo sobre a mortalidade de larvas de A. mellifera.bitstream/CNPUV-2010/12000/1/boletim-97.pd
Nambu monopoles interacting with lattice defects in two-dimensional artificial square spin ice
The interactions between an excitation (similar to a pair of Nambu monopoles)
and a lattice defect are studied in an artificial two-dimensional square spin
ice. This is done by considering a square array of islands containing only one
island different from all others. This difference is incorporated in the
magnetic moment (spin) of the "imperfect" island and several cases are studied,
including the special situation in which this distinct spin is zero (vacancy).
We have shown that the two extreme points of a malformed island behave like two
opposite magnetic charges. Then, the effective interaction between a pair of
Nambu monopoles with the deformed island is a problem involving four magnetic
charges (two pairs of opposite poles) and a string. We also sketch the
configuration of the field lines of these four charges to confirm this picture.
The influence of the string on this interaction decays rapidly with the string
distance from the defect.Comment: 7 pages, 13 figure
An eccentric companion at the edge of the brown dwarf desert orbiting the 2.4 Msun giant star HIP67537
We report the discovery of a substellar companion around the giant star
HIP67537. Based on precision radial velocity measurements from CHIRON and FEROS
high-resolution spectroscopic data, we derived the following orbital elements
for HIP67537: msin = 11.1 M,
= 4.9 AU and = 0.59. Considering
random inclination angles, this object has 65% probability to be
above the theoretical deuterium-burning limit, thus it is one of the few known
objects in the planet to brown-dwarf transition region. In addition, we
analyzed the Hipparcos astrometric data of this star, from which we derived a
minimum inclination angle for the companion of 2 deg. This value
corresponds to an upper mass limit of 0.3 M, therefore the
probability that HIP67537 is stellar in nature is 7%. The large
mass of the host star and the high orbital eccentricity makes HIP67537 a
very interesting and rare substellar object. This is the second candidate
companion in the brown dwarf desert detected in the sample of intermediate-mass
stars targeted by the EXPRESS radial velocity program, which corresponds to a
detection fraction of = 1.6%. This value is larger than the
fraction observed in solar-type stars, providing new observational evidence of
an enhanced formation efficiency of massive substellar companions in massive
disks. Finally, we speculate about different formation channels for this
object.Comment: Accepted for publication to A&
Association of slow darkening gene 'SD' with grain quality traits in carioca bean and new candidate marker.
The seed darkens during storage becoming less acceptable to consumers and depreciation of the economic value. Cultivars with delayed grain darkening associated with reduced cooking time after storage will be advantageous for the farmer and seed dealers. Grain storage for longer periods allows flexibility, i.e., the producer can await better prices on the market
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