4,771 research outputs found
Lepton-Flavour-Violation in SUSY Models with and without R-parity
We discuss Lepton-Flavour-Violating phenomena such as ,
, and conversion in nuclei in SUSY models with and
without R-parity. We stress that experimental searches for all the LFV
processes are important to distinguish between the different models.Comment: 4 pages, talk given at 8th International Workshop on Deep Inelastic
Scattering and QCD (DIS 2000), Liverpool, England, 25-30 Apr 200
Michel parameters for decays in a general two Higgs doublet model with flavor violation
In a general two Higgs doublet model (2HDM), the anomaly of muon anomalous
magnetic moment (muon g-2) can be explained by flavor violating
Yukawa couplings, motivated by the recent CMS excess in Higgs boson decay
. We study Michel parameters for decays in the 2HDM with the lepton flavor
violation, and show that they can be sensitive to the flavor structure as well
as the Lorentz and chiral structures of the model. We find that the correction
to the Michel parameter in is
correlated to the contribution to the muon g-2, and it can be as large as
in the parameter region where the flavor violating
Yukawa couplings explain the muon g-2 anomaly. Therefore the precision
measurement of the Michel parameter at the level of would
significantly probe the interesting parameter space for the solution to the
muon g-2 anomaly.Comment: 16 pages, 2 figure
New physics for muon anomalous magnetic moment and its electroweak precision analysis
About 3 sigma deviation from the standard model prediction of muon anomalous
magnetic moment (muon g-2) has been reported. We consider new physics beyond
the standard model which has new Yukawa interactions with muon. We compute new
contributions to muon g-2 and corrections to electroweak observables, and show
the consistent region of parameter space. We find that in a simple model where
the chirality flip of muon occurs only in the external muon line in one-loop
muon g-2 diagrams, it is necessary to introduce the relatively large new Yukawa
coupling and the electroweak scale new particles. On the other hand, in a model
where the chirality flip can occur in the internal fermion line of one loop
muon g-2 diagrams, we can obtain favorable g-2 contributions without large
Yukawa coupling, and they are consistent with the precision electroweak
observables. Finally, we discuss effects of new particles for muon g-2 on the
Higgs boson decay h to 2 photons and direct productions of these particles at
the LHC experiment.Comment: 31 pages, 20 figure
Lepton-flavor-violating Higgs decay and muon anomalous magnetic moment in a general two Higgs doublet model
A two Higgs doublet model (2HDM) is one of the minimal extensions of the
Standard Model (SM), and it is well-known that the general setup predicts the
flavor-violating phenomena, mediated by neutral Higgs interactions. Recently
the CMS collaboration has reported an excess of the lepton-flavor-violating
Higgs decay in channel with a significance of 2.5 . We investigate the CMS excess in a general 2HDM with tree-level Flavor
Changing Neutral Currents (FCNCs), and discuss its impact on the other physical
observations. Especially, we see that the FCNCs relevant to the excess can
enhance the neutral Higgs contributions to the muon anomalous magnetic moment,
and can resolve the discrepancy between the measured value and the SM
prediction. We also find that the couplings to be consistent with the muon g-2
anomaly as well as the CMS excess in predict the sizable
rate of , which is within the reach of future B
factory.Comment: 6 pages, 3 figures, revised Fig.3, corrected Eq. (12), added
references, accepted for publication in JHE
A Gauge Mediation Model of Dynamical Supersymmetry Breaking without Color Instability
We construct a gauge mediation model of dynamical supersymmetry breaking
(DSB) based on a vector-like gauge theory, in which there is a unique
color-preserving true vacuum. The DSB scale turns out to be as
high as , since the transmission of the DSB
effects to the standard model sector is completed through much higher loops.
This model is perfectly natural and phenomenologically consistent. We also
stress that the dangerous D-term problem for the messenger U(1)_m is
automatically solved by a charge conjugation symmetry in the vector-like gauge
theory.Comment: 11 pages, Late
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Residual stress field of HIPed silicon nitride rolling elements
The residual stress field of HIPed Si3N4 rolling elements were studied. Two kinds of HIPed Si3N4 ball blanks self-finished at different nominal lapping loads ranging from 1.3 to 10.87 kgf/ball and four kinds of commercially finished 1/2 in (12.7 mm) HIPed Si3N4 balls before, during and after RCF tests were investigated. The experimental results showed that in the finishing process of HIPed Si3N4 rolling elements. the surface and subsurface compressive residual stress induced is proportional to the lapping load applied. There was initially a high compressive residual stress layer on the HIPed Si3N4 ball blanks and this layer is mostly removed during the finishing process. During the rolling contact fatigue process of HIPed Si3N4 rolling elements, the residual stresses on the rolling track will change dramatically as RCF proceeds
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