3,733 research outputs found
Evading the Few TeV Perturbative Limit in 3-3-1 Models
Some versions of the electroweak SU(3)_L\otimesU(1)_X models cannot be
treated within perturbation theory at energies of few TeV. An extended version
for these models is proposed which is perturbative even at TeV scale posing no
threatening inconsistency for test at future colliders. The extension presented
here needs the addition of three octets of vector leptons, which leave three
new leptonic isotriplets in the SU(2)_L\otimesU(1)_Y subgroup. With this
representation content the running of the electroweak mixing angle, , is such that decreases with the increase of the
energy scale , when only the light states of the Standard Model group are
considered. The neutral exotic gauge boson marks then a new symmetry
frontier.Comment: 15 pages, 2 figures, minor correction
Type II Seesaw and a Gauge Model for the Bimaximal Mixing Explanation of Neutrino Puzzles
We present a gauge model for the bimaximal mixing pattern among the neutrinos
that explains both the atmospheric and solar neutrino data via large angle
vacuum oscillation among the three known neutrinos. The model does not include
righthanded neutrinos but additional Higgs triplets which acquire naturally
small vev's due to the type II seesaw mechanism. A combination of global
and symmetries constrain the mass matrix for both
charged leptons and neutrinos in such a way that the bimaximal pattern emerges
naturally at the tree level and needed splittings among neutrinos at the one
loop level. This model predicts observable branching ratios for , which could be used to test it.Comment: Latex file, 8 pages, five figures include
Five-Dimensional QED, Muon Pair Production and Correction to the Coulomb Potential
We consider QED in five dimensions in a configuration where matter is
localized on a 3-brane while foton propagates in the bulk. The idea is to
investigate the effects of the Kaluza-Klein modes of the photon in the
relativistic regime, but in low energy, and in the nonrelativistic regime. In
the relativistic regime, we calculate the cross section for the reaction . We compare our theoretical result with a precise
measurement of this cross section at GeV. As result, we
extract a lower bound on the size of the extra dimension. In the
nonrelativistic regime, we derive the contribution for the Coulomb potential
due to the whole tower of the Kaluza-Klein excited modes of the photon. We use
the modified potential to calculate the Rutherford scattering differential
cross section.Comment: minor changes, three new refs. added, to appear in IJMP
Neutrino Decay and Neutrinoless Double Beta Decay in a 3-3-1 Model
In this work we show that the implementation of spontaneous breaking of the
lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast
neutrino decay with majoron emission and generates a bunch of new contributions
to the neutrinoless double beta decay.Comment: Version accepted for publication in the Phys. Rev.
Transferência de nutrientes por vias hidrológicas em três pequenas bacias sob uso agrícola familiar no nordeste paraense: chuva, escoamento superficial em solos e águas fluviais.
Poster 651. Disponível também on-line
The Left-Right SU(3)(L)xSU(3)(R)xU(1)(X) Model with Light, keV and Heavy Neutrinos
We construct a full left-right model for the electroweak interactions based
on the gauge symmetry. The fermion
content of the model is such that anomaly cancellation restricts the number of
families to be a multiple of three. One of the most important features of the
model is the joint presence of three light active neutrinos, three additional
neutrinos at keV mass scale, and six heavy ones with masses
around\textbf{} GeV. They form a well-motivated part of the spectrum
in the sense they address challenging problems related to neutrino oscillation,
warm dark matter, and baryogenesis through leptogenesis.Comment: 11 pages. Small corrections and typos fixed. Accepted for publication
in PR
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