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1.
The SO(3) gauge extension of SM, which is proposed to present a successful explanation for the observed small masses of neutrino and the nearly tri-bimaximal neutrino mixing, predicted the vector-like SO(3) triplet Majorana neutrinos and SUL(2) double Higgs bosons. In this work we calculate branching ratios of the charged lepton flavor violating decays lIlJV (V = γ, Z) induced by these Majorana neutrinos and Higgs bosons. We find that under the model parameters constrained by experimental bounds on the decays Z →lIlJ, the branching ratio of decays lI→lJγ can be up to 10^-10, which may be accessible at the future experiments.  相似文献   

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Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,where P and V denote a pseudoscalar meson(π, η or η′) and a vector meson(ρ0, ω or φ), respectively. We find that the contributions of the 331 model to the LFV decays τ→μM mainly come from the new neutral gauge boson Z′. The 331 model considered in this paper can not make the values of the branching ratio Br(τ→μM) approach the corresponding experimental upper limits.  相似文献   

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We embed a theory with Z′ gauge boson (related to an extra U(1) gauge group) into a supersymmetric GUT theory based on SO(10). Two possible sequences of SO(10) breaking via VEVs of appropriate Higgs fields are considered. Gauge coupling unification provides constraints on the low energy values of two additional gauge coupling constants related to Z′ interactions with fermions. Our main purpose is to investigate in detail the freedom in these two values due to different scales of subsequent SO(10) breaking and unknown threshold mass corrections in the gauge RGEs. These corrections are mainly generated by Higgs representations and can be large because of the large dimensions of these representations. To account for many free mass parameters, effective threshold mass corrections have been introduced. Analytic results that show the allowed regions of values of two additional gauge coupling constants have been derived at 1-loop level. For a few points in parameter-space that belong to one of these allowed regions 1-loop running of gauge coupling constants has been compared with more precise running, which is 2-loop for gauge coupling constants and 1-loop for Yukawa coupling constants. 1-loop results have been compared with experimental constraints from electroweak precision tests and from the most recent LHC data.  相似文献   

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In this paper, gauge constrained conditions and quantization of SU(N) gauge theories are analysed by means of Dirac's formalism. In the framework of algebraic dynamics, gauge invariance, Gauss law and Ward identities are discussed. With use of the version of conservation law in correlation dynamics, the conserved Gauss law and Ward identities related to residual gauge invariance can be transformed into initial value problems.  相似文献   

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A study is made of the processes of annihilation of an arbitrarily polarized ee+ pair into a pair of particles of spin 0, 1/2, 1, and 3/2 in the (Z)-resonance region.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 53–59, October, 1978.  相似文献   

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In this paper we study the spinor constructions of gauge fluxes and Ramond-Ramond fields on noncommutative tori T^d up to d=6. In which the spinor and conjugate spinor are distinguished and dual bases are also introduced.So that we can express the Chern-Simons Lagrangian in toroidal compactification as a product of spinors.  相似文献   

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The lepton flavor violating process μ - eγ has been previously studied in a model of electroweak-scale right-handed neutrinos. In that work the decay amplitude was computed in unitarity gauge, augmented by some technical considerations that correct the leading term thus obtained. This complication arises because the mixing matrices appearing in the weak charged currents are not unitary in the model. In this paper, we recalculate the amplitude in Re gauge. The cancellation of the ξ dependence in the final result serves as a useful check to both the obtained amplitude and the technical points made in the previous work.  相似文献   

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We address the effects of the new physics predicted by theSU(3) l ×U(1) X model on the precision electroweak measurements. We consider bothZ–Z mixing and one-loop oblique corrections, using a combination of neutral gauge boson mixing parameters and the parametersS andT. At tree level, we obtain strong limits on theZ–Z mixing angle, –0.0006<0.0042 and="> 490$$ " align="middle" border="0"> GeV (both at 90% C.L.). The radiative corrections lead toT>0 if the new Higgs are heavy, which bounds the Higgs masses to be less than a few TeV.S can have either sign depending on the Higgs mass spectrum. Future experiments may soon place strong restrictions on this model, thus making it eminently testable.  相似文献   

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The family symmetry SU(3)U(1) is proposed to solve flavor problems about fermion masses and flavor mixings.It is breaking is implemented by some flavon fields at the high-energy scale.In addition a discrete group Z 2 is introduced to generate tiny neutrino masses,which is broken by a real singlet scalar field at the middle-energy scale.The low-energy effective theory is elegantly obtained after all of super-heavy fermions are integrated out and decoupling.All the fermion mass matrices are regularly characterized by four fundamental matrices and thirteen parameters.The model can perfectly fit and account for all the current experimental data about the fermion masses and flavor mixings,in particular,it finely predicts the first generation quark masses and the values of θ l 13 and J l CP in neutrino physics.All of the results are promising to be tested in the future experiments.  相似文献   

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One could compare the discovery of a new particle to a big shining firework,lighting up the night sky.But sometimes discoveries can be subtle,less flamboyant,and still point to the existence of new particles in an indirect way.  相似文献   

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The electron spin resonance spectrum of the radical NH(SO3 - trapped in a single crystal of potassium sulphamate is interpreted. The hyperfine couplings for the hydrogen and nitrogen nuclei are given. The radical is planar, the unpaired electron occupying an orbital of π symmetry being predominantly a nitrogen 2p orbital.  相似文献   

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《Physics letters. [Part B]》1988,201(2):279-282
We estimate in a current algebra framework the hadronic matrix elements relevant to the weak B→pp̄π (π) transitions measured recently. The results so obtained are in agreement with the observed values.  相似文献   

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The tetradic Lorentz-gauge invariant formulation of the SU(2) × U(1) theory in S3 × R space-time is presented and the general gauge covariant Dirac-Klein-Gordon-Maxwell-Yang-Mills equations are derived. A direct comparison of these equations to those of the SU(2) × U(1) gauge theory on Minkowskian background points out major differences effectively induced by the minimally coupling to S3 × R gravity.  相似文献   

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