98 research outputs found
Une observation d’un goitre sur dysgénésie thyroïdienne pré-sternale
L'hétérotopie thyroïdienne est une localisation anormale de tissus thyroïdiens normaux coexistant avec un organe normal et de localisation normale. Elle se distingue de l'ectopie thyroïdienne et d'une métastase du cancer de la thyroïde. Nous rapportons un cas d'hétérotopie thyroïdienne pré-sternale chez une femme de 65 ans afin de discuter le mécanisme de la migration de la thyroïde, le problème diagnostique et thérapeutique posé par cette topographie exceptionnelle. L'origine thyroïdienne de la masse est confirmée par l'histologie. Dans les lieux isolés, la chirurgie d'exérèse reste le seul moyen pour avoir le diagnostic et pour traiter les patients
Softly Broken A_4 Symmetry for Nearly Degenerate Neutrino Masses
The leptonic Higgs doublet model of neutrino masses is implemented with an
A_4 discrete symmetry (the even permutation of 4 objects or equivalently the
symmetry of the tetrahedron) which has 4 irreducible representations: 1, 1',
1'', and 3. The resulting spontaneous and soft breaking of A_4 provides a
realistic model of charged-lepton masses as well as a nearly degenerate
neutrino mass matrix. Phenomenological consequences at and below the TeV scale
are discussed.Comment: 11 pages, no figur
Supersymmetric economical 3-3-1 model
The supersymmetric extension of the economical 3-3-1 model is presented. The
constraint equations and the gauge boson identification establish a relation
between the vacuum expectation values (VEVs) at the top and bottom elements of
the Higgs triplet and its supersymmetric counterpart .
Because of this relation, the exact diagonalization of neutral gauge boson
sector has been performed. The gauge bosons and their associated Goldstone ones
mix in the same way as in non-supersymmetric version. This is also correct in
the case of gauginos. The eigenvalues and eigenstates in the Higgs sector are
derived. The model contains a heavy neutral Higgs boson with mass equal to
those of the neutral non-Hermitian gauge boson and a charged scalar with
mass equal to those of the boson in the standard model, i. e. . This result is in good agreement with the present
estimation: GeV, CL= 95 %. We also show that the boson
sector and the fermion sector gain masses in the same way as in the
non-supersymmetric case.Comment: 33 page
Higgs phenomenology of supersymmetric economical 3-3-1 model
We explore the Higgs sector in the supersymmetric economical 3-3-1 model and
find new features in this sector. The charged Higgs sector is revised i.e., in
difference of the previous work, the exact eigenvalues and states are obtained
without any approximation. In this model, there are three Higgs bosons having
masses equal to that of the gauge bosons--the W and extra X and Y. There is one
scalar boson with mass of 91.4 GeV, which is closed to the boson mass and
in good agreement with present limit: 89.8 GeV at 95% CL. The condition of
eliminating for charged scalar tachyon leads to splitting of VEV at the first
symmetry breaking, namely, . The interactions among the
standard model gauge bosons and scalar fields in the framework of the
supersymmetric economical 3-3-1 model are presented. From these couplings, at
some limit, almost scalar Higgs fields can be recognized in accordance with the
standard model. The hadronic cross section for production of the bilepton
charged Higgs boson at the CERN LHC in the effective vector boson approximation
is calculated. Numerical evaluation shows that the cross section can exceed
35.8 fb.Comment: 33 pages, 1 figur
Supersymmetric Model of Muon Anomalous Magnetic Moment and Neutrino Masses
We propose the novel lepton-number relationship , which
is uniquely realized by the interaction in supersymmetry and may account for a possibly large
muon anomalous magnetic moment. Neutrino masses (with bimaximal mixing) may be
generated from the spontaneous and soft breaking of this lepton symmetry.Comment: 10 pages, including 2 figure
Anomalous Neutrino Interaction, Muon g-2, and Atomic Parity Nonconservation
We propose a simple unified description of two recent precision measurements
which suggest new physics beyond the Standard Model of particle interactions,
i.e. the deviation of in deep inelastic neutrino-nucleon
scattering and that of the anomalous magnetic moment of the muon. Our proposal
is also consistent with a third precision measurement, i.e. that of parity
nonconservation in atomic Cesium, which agrees with the Standard Model.Comment: 9 pages, including 1 figure, latest muon g-2 information adde
The seesaw mechanism at TeV scale in the 3-3-1 model with right-handed neutrinos
We implement the seesaw mechanism in the 3-3-1 model with right-handed
neutrinos. This is accomplished by the introduction of a scalar sextet into the
model and the spontaneous violation of the lepton number. We identify the
Majoron as a singlet under symmetry, which makes it
safe under the current bounds imposed by electroweak data. The main result of
this work is that the seesaw mechanism works already at TeV scale with the
outcome that the right-handed neutrino masses lie in the electroweak scale, in
the range from MeV to tens of GeV. This window provides a great opportunity to
test their appearance at current detectors, though when we contrast our results
with some previous analysis concerning detection sensitivity at LHC, we
conclude that further work is needed in order to validate this search.Comment: about 13 pages, no figure
Lepton masses in a supersymmetric 3-3-1 model
We consider the mass generation for both charginos and neutralinos in a 3-3-1
supersymmetric model. We show that R-parity breaking interactions leave the
electron and one of the neutrinos massless at the tree level. However the same
interactions induce masses for these particles at the 1-loop level. Unlike the
similar situation in the MSSM the masses of the neutralinos are related to the
masses of the charginos.Comment: RevTex, 11 pages incluing 2 .eps figures. Extended published versio
Seesaw tau lepton mass and calculable neutrino masses in a 3-3-1 model
In a version of the 3-3-1 model proposed by Duong and Ma the introduction of
the scalar sextet for giving mass to the charged leptons is avoided by adding a
singlet charged lepton. We show that in this case the lepton gains mass
through a seesaw--like mechanism. Besides we show how to generate neutrino
masses at the tree and at the 1-loop level with the respective
Maki-Nakagawa-Sakata leptonic mixing matrices.Comment: revtex, 5 pages and one eps figure. Published versio
Search for the lepton-family-number nonconserving decay \mu -> e + \gamma
The MEGA experiment, which searched for the muon- and electron-number
violating decay \mu -> e + \gamma, is described. The spectrometer system, the
calibrations, the data taking procedures, the data analysis, and the
sensitivity of the experiment are discussed. The most stringent upper limit on
the branching ratio of \mu -> e + \gamma) < 1.2 x 10^{-11} was obtained
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