Cabibbo angles without scalars

A simple model of dynamical symmetry breaking is presented in which the mass matrices of the up and down quarks are related to a (ETC) vector-boson mass-matrix in the 10–100 TeV range. Realistic quark masses and Cabibbo angles can be obtained. The problem of flavour-changing neutral interactions in theories of dynamical symmetry breaking is discussed in the context of this model.     

On a unified theory of electromagnetism and weak interaction

A unified theory of weak and electromagnetic interaction has been developed on the basis of the assumption that the charge and mass of a lepton is of dynamical origin. According to this model, the spontaneous breakdown of symmetry generates the photon as a Goldstone boson.     

On planar fermions with quartic interaction at finite temperature and density

We study the breaking of parity symmetry in the 2+1 Gross-Neveu model at finite temperature with chemical potential μ, in the presence of an external magnetic field. We find that the requirement of gauge invariance, which is considered mandatory in the presence of gauge fields, breaks parity at any finite temperature and provides for dynamical mass generation, preventing symmetry restoration for any non-vanishing μ. The dynamical mass becomes negligibly small as temperature is raised. Received 4 April 2002 / Received in final form 12 July 2002 Published online 15 October 2002 RID="a" ID="a"e-mail: cabra@venus.fisica.unlp.edu.ar     

Dynamically Broken Supergauge Symmetries

The dynamical breaking of the supergauge symmetries in the massless supergauge Wess Zumino model isdiscussed without adding the Fayet-Iliopoulos term to the Lagrangian. It is shown, in terms of the Nambu-Jona-Lasiniomechanism, that the supersymmetry breaking and the gauge symmetry breaking can be realized dynamically. It is alsoshown that the dynamical breaking moves the vacuum expectation values of two scalar fields away from zero. In order torestore the symmetry of the vacuum, one of the two scalar fields is translated and at the same time the mass spectrumis changed too.     

DYNAMICAL SYMMETRY BREAKING IN MODELS OF SPIMOR FIELDS WITH QUARTIC INTERACTIONS IN (1+1) DIMENSIONS

A nonperturbative method, namely, variarional method together with canonical transformations, is developtd to study dyndcal symmetry breaking. This method has been applied in the models of two dimensional massless fermion fields with quartic interactions. The results imply that the mechanism of dynamical symmetry breaking bears some analogy to the phenomenon of superconductivity. The new vacuum |õ> is just a relativistic BCS groundstate, In this vacuum |õ>, we can observe a quasi-particle with mass "MP" Furthermore, correlative vacuum |õ> exists and the mesons emerge with masses "O" and "2M_F". It is also shown that dynamical symmetry breaking always occurs in the models with infrared slavery and asymptotic freedom, while it is meaningless to dis-cuss dynamical symmetry breaking in infrared stable theory.     

The Effect of Bare Quark Mass on the Pion Properties in BS Formalism Containing a Confining Term

Using the SD equation and the covariant BS equation, we investigate dynamical chiral symmetry breaking in the presence of a bare quark mass in a QCD motivated model containing a confining interaction. The bare quark mass m₀ corresponding to the physical mass of the pion and corrections to the dynamical quark mass and the pion decay constant due to mo are calculated. The results are consistent with the notion of chiral perturbatiyn and predictions of the current algebra.     

Electron mass operator in a strong magnetic field and dynamical chiral symmetry breaking

The electron mass operator in a strong magnetic field is calculated. The contribution of higher Landau levels of virtual electrons, along with the ground Landau level, is shown to be essential in the leading log approximation. The effect of the electron dynamical mass generation by a magnetic field is investigated. In a model with N charged fermions, it is shown that some critical number N(cr) exists for any value of the electromagnetic coupling constant alpha, such that the fermion dynamical mass is generated with a doublet splitting for NN(cr), thus leaving the chiral symmetry unbroken.     

Symmetries of the interacting boson model

This contribution reviews the symmetry properties of the interacting boson model of Arima and Iachello. While the concept of a dynamical symmetry is by now a familiar one, this is not necessarily so for the extended notions of partial dynamical symmetry and quasi dynamical symmetry, which can be beautifully illustrated in the context of the interacting boson model. The main conclusion of the analysis is that dynamical symmetries are scarce while their partial and quasi extensions are ubiquitous.     

The Average Nucleon Density in Intrinsic State of FDSM SO(6)

The average nucleon density in the intrinsic state of SO(6) of the fermion dynamical symmetry model is given. The relation between the geometric model and the fermion dynamical symmetry model is established microscopically in terms of the bridge of the nucleon density. An approximate expression of deformed parameters in the geometric model is obtained analytically by comparing the nucleon density of the fermion dynamical symmetry model with that of the geometric model.     

Spontaneous symmetry breaking in QCD

We study dynamical chiral symmetry breaking in massless QCD by the use of the generalized Hartree-Fock method. As the order parameter of chiral symmetry we choose the dynamical quark mass in the zero momentum limit which we call low energy quark mass. We calculate the low energy mass to the second order of diagrammatic expansion around shifted perturbative vacuum. We then show that the mass is finite and renormalization group invariant. After the improvement of the result by the method of effective charges we estimate the mass in the true vacuum under the gap and stationarity conditions and demonstrate that both of them produce non-zero mass proportional to a conventional scale, which breaks down the chiral symmetry.     

Description of the Superdeformed Bands of Odd-Odd Nuclei in A ～ 80 Region

Properties of the superdeformed bands of odd-odd nuclei in A～80 mass region are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry. The obtained γ-ray energies, and the dynamical moments of inertia agree with experimental data. It shows that this approach is quite powerful in describing odd-odd nuclei in A～80 mass region.     

The fermion condensate of the Nambu-Jona-Lasinio model in Light Cone quantisation

We investigate the incorporation of condensates in Light Cone quantisation in the frame-work of the Nambu-Jona-Lasinio model. Although it is shown that the physical and perturbative vacua are identical, a gap equation for the dynamical quark mass is obtained and chiral symmetry is dynamically broken. The complete fermion condensate is found in the perturbative vacuum. The corresponding Goldstone mode is a zero mass bound state of the Weinberg equation.     

Dynamical electroweak symmetry breaking with a heavy fourth generation

A heavy fourth generation with a mass of the order of 400 GeV or more could trigger dynamical electroweak symmetry breaking by forming condensates through the exchange of a fundamental Higgs scalar doublet. The dynamics leading to these condensates is studied within the framework of the Schwinger–Dyson equation. This scenario leads to the presence of three (two composite and one fundamental) Higgs doublets, with interesting phenomenological implications. In addition, this dynamical phenomenon occurs in the vicinity of the energy scale where the restoration of scale symmetry might happen.     

离散差分序列变质量Hamilton系统的Lie对称性与Noether守恒量

本文研究离散差分序列变质量Hamilton系统的Lie对称性与Noether守恒量. 构建了离散差分序列变质量Hamilton系统的差分动力学方程, 给出了离散差分序列变质量Hamilton系统差分动力学方程在无限小变 换群下的Lie对称性的确定方程和定义, 得到了离散力学系统Lie对称性导致Noether守恒量的条件及形式, 举例说明结果的应用. 关键词： 离散力学 Hamilton系统 Lie对称性 Noether守恒量     

Heavy axions from strong broken horizontal gauge symmetry

We study the consequences of the existence and breaking of a Peccei-Quinn symmetry within the context of a dynamical model of electroweak symmetry breaking based on broken gauged flavour symmetries. We perform an estimate of the axion mass by including flavour instanton effects and show that, for low cut-offs, the axion is sufficiently massive to prevent it from being phenomenologically unacceptable. We conclude with an examination of the strong CP problem and show that our axion cannot solve the problem, though we indicate ways in which the model can be extended so that the strong CP problem is solved.     

CONFORMAL INVARIANCE AND PARTICLE ASPECTS IN GENERAL RELATIVITY

We study the breakdown of conformal symmetry in a conformally invariant gravitational model. The symmetry breaking is introduced by defining a preferred conformal frame in terms of the large scale characteristics of the universe. In this context we show that a local change of the preferred conformal frame results in a Hamilton-Jacobi equation describing a particle with adjustable mass. In this equation the dynamical characteristics of the particle substantially depends on the applied conformal factor and local geometry. Relevant interpretations of the results are also discussed.     

Aspects of the super-unification of strong,electroweak and gravitational interactions

We develop a strategy for extracting low-energy phenomenological four-dimensional physics from the superstring. We discuss supersymmetry and gauge symmetry breaking, emphasizing key ingredients in the construction of a realistic model based on Calabi-Yau compactification. The incorporation of a no-scale mechanism for the dynamical generation of the electroweak gauge hierarchy imposes a unique choice of the gauge group SU(3) × SU(2) × U(1)², an almost unique set of matter fields and of Yukawa couplings. Our phenomenological analysis of this model includes the derivation of bounds on the mass of the new neutral gauge boson from the Z⁰ boson mass, low-energy neutral currents, and cosmology. We calculate the ratios of sparticle masses and give estimates of their magnitudes. These are based on detailed dynamical calculations demonstrating the feasibility of weak gauge symmetry breaking, made possible by radiative corrections to supersymmetry breaking initiated by a gaugino mass.     

Systematic Study on the Superdeformed Bands of Double Odd Nuclei in A～130 Region

Properties of the superdeformed bands of odd-odd nuclei in A～130 mass region are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry. The obtained γ-ray energies, the dynamical moments of inertia, and energy differences △Eγ - △Eγ^ref agree wlth experimental data. It shows that this approach is quite powerful in describing odd-odd nuclei in 130 mass region.     

Partially composite two-Higgs doublet model

In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type attractive fourfermion interactions, which can break electroweak symmetry dynamically with accompanying composite Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on the coupling and mass parameters originating at a compositeness scale Λ. The phenomenology of this model is discussed including the collider phenomenology at LHC and ILC.