1,203 research outputs found
Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos
The static electromagnetic properties of the boson, and
, are calculated in the SU_L(3)} \times U_X(1) model with
right-handed neutrinos. The new contributions from this model arise from the
gauge and scalar sectors. In the gauge sector there is a new contribution from
a complex neutral gauge boson and a singly-charged gauge boson .
The mass of these gauge bosons, called bileptons, is expected to be in the
range of a few hundreds of GeV according to the current bounds from
experimental data. If the bilepton masses are of the order of 200 GeV, the size
of their contribution is similar to that obtained in other weakly coupled
theories. However the contributions to both and are
negligible for very heavy or degenerate bileptons. As for the scalar sector, an
scenario is examined in which the contribution to the form factors is
identical to that of a two-Higgs-doublet model. It is found that this sector
would not give large corrections to and .Comment: New material included. Final version to apppear in Physical Review
Scalar Potential Without Cubic Term in 3-3-1 Models Without Exotic Electric Charges
A detailed study of the criteria for stability of the scalar potential, and
the proper electroweak symmetry breaking pattern in some 3-3-1 models without
exotic electric charges is presented. In this paper we concentrate in a scalar
sector with three Higgs scalar triplets, with a potential that does not include
the cubic term, due to the presence of a discrete symmetry. For the analysis we
use, and improve, a method previously developed to study the scalar potential
in the two-Higgs-doublet extension of the standard model. Our main result is to
show the consistency of those 3-3-1 models without exotic electric charges.Comment: 19 page
The 3-3-1 model with S_4 flavor symmetry
We construct a 3-3-1 model based on family symmetry S_4 responsible for the
neutrino and quark masses. The tribimaximal neutrino mixing and the diagonal
quark mixing have been obtained. The new lepton charge \mathcal{L} related to
the ordinary lepton charge L and a SU(3) charge by L=2/\sqrt{3} T_8+\mathcal{L}
and the lepton parity P_l=(-)^L known as a residual symmetry of L have been
introduced which provide insights in this kind of model. The expected vacuum
alignments resulting in potential minimization can origin from appropriate
violation terms of S_4 and \mathcal{L}. The smallness of seesaw contributions
can be explained from the existence of such terms too. If P_l is not broken by
the vacuum values of the scalar fields, there is no mixing between the exotic
and the ordinary quarks at the tree level.Comment: 20 pages, revised versio
SU(3)_c X SU(4)_L X U(1)_x without exotic electric charges
We present an extension of the Standard Model to the local gauge group
with a family non-universal treatment
and anomalies canceled among the three families in a nontrivial fashion. The
mass scales, the gauge boson masses, and the masses for the spin 1/2 particles
in the model are analyzed. The neutral currents coupled to all neutral vector
bosons in the model are studied, and particular values of the parameters are
used in order to simplify the mixing between the three neutral currents present
in the theory, mixing which is further constrained by experimental results from
the CERN LEP, SLAC Linear Collider, and atomic parity violation.Comment: RevTeX, 11 pages, 1 figure. Several formulas corrected. One reference
added. Accepted for publication in Phys. Rev.
Chromomagnetic Dipole Moment of the Top Quark Revisited
We study the complete one-loop contributions to the chromagnetic dipole
moment of the top quark in the Standard Model, two Higgs doublet
models, topcolor assited technicolor models (TC2), 331 models and extended
models with a single extra dimension. We find that the SM predicts
and that the predictions of the other models are also
consitent with the constraints imposed on by low-energy
precision measurements.Comment: 20 pages, 5 figures, Updat
Phenomenological aspects of the exotic quark in 331 models
In the context of 331 models we analyze the phenomenology of exotic
quarks with electric charge 2/3. We establish bounds for the corresponding
masses and mixing angles and study the decay modes , and . It
is found that the decays into scalars are strongly dependent on the model
parameters, and can be the dominant ones in a scenario with approximate flavor
symmetry.Comment: 11 pages, 2 figure
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using
ultracold atoms in an optical lattice. We investigate the phase evolution of an
array of essentially non-interacting matter waves and observe matter-wave
collapse and revival in the form of a Talbot interference pattern. By using
long expansion times, we image momentum space with sub-recoil resolution,
allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure
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