高阶微商系统中正则Ward恒等式和Abel规范理论中动力学质量的产生

基于含复合场的正则Ward恒等式，研究了含高阶微商的Abel理论中动力学规范对称破缺.得到了包括费米子和束缚态的质量谱.讨论了高阶微商项的影响. 关键词： 正则Ward恒等式 约束 动力学对称破缺 Abel规范理论     

On the dynamical mass generation in confining Yang-Mills theories

The dynamical mass generation for gluons is discussed in Euclidean Yang-Mills theories supplemented with a renormalizable mass term. The mass parameter is not free, being determined in a self-consistent way through a gap equation which obeys the renormalization group. The example of the Landau gauge is worked out explicitly at one-loop order. The issues of the unitarity and of the gauge invariance are also addressed.     

Radiative mass generation in perturbation theory and the renormalization group

The mechanism of dynamical mass generation is investigated in perturbation theory for the spontaneously broken supersymmetry model of O'Raifeartaigh. The generated mass obeys an homogeneous renormalization group equation. The compatibility of the perturbation solution with the exact solutions spectrum of the renormalization group equation is shown.     

Long range dynamics and broken symmetries in gauge models. The Stückelberg-Kibble model

The general algebraic features associated to long range dynamics like the problem of removing the infrared cutoff, the definition of the algebraic dynamics and the occurrence of variables at infinity, the essential localization (seizing of the vacuum), the effective dynamics and its covariance group (dynamical symmetry group), the generalization of Goldstone's theorem and the non-trivial Goldstone spectrum, the mass/energy gap generation by the non-trivial classical motion of the variables at infinity are explicitly shown in the Kibble model as a prototype of gauge models exhibiting the Higgs phenomenon. The relation between mass generation in the Higgs phenomenon and the plasma energy gap is also discussed.Work supported in part by INFN, Sezione di Pisa     

Massive mesons in Weyl–Dirac theory

In order to study the mass generation of the vector fields in the framework of a conformal invariant gravitational model, the Weyl–Dirac theory is considered. The mass of the Weyl’s meson fields plays a principal role in this theory, it connects basically the conformal and gauge symmetries. We estimate this mass by using the large-scale characteristics of the observed universe. To do this we firstly specify a preferred conformal frame as a cosmological frame, then in this frame, we introduce an exact possible solution of the theory. We also study the dynamical effect of the massive vector meson fields on the trajectories of an elementary particle. We show that a local change of the cosmological frame leads to a Hamilton–Jacobi equation describing a particle with an adjustable mass. The dynamical effect of the massive vector meson field presents itself in the form of a correction term for the mass of the particle.     

Some solutions of the equations of motion of the relativistic string with massive ends

The classical theory is discussed for the relativistic string with point masses at its ends. The dynamical equations are solved for the class of motions of this system when the time evolution parameter τ is the proper time of both massive string ends. In this case the solution of the boundary equations is given by the almost periodic functions. Constraints on the normal modes resulting from the orthonormal gauge conditions differ essentially from the Virasoro ones. Incidentally one obtains an exact solution for the half-infinite string with mass at one end. It is also proved that the exact solution for the string with massive ends cannot be a periodic function.     

Vacuum alignment in supersymmetric gauge theories

The vacuum alignment problem is analyzed in the context of supersymmetric gauge theories with dynamical symmetry breaking. Three cases are distinguished, depending on whether the vacuum expectation value of the weak gauge current superfield in vacuum characterized by the orientation Ω is zero for all Ω, for some Ω, or for no Ω. In the first case, a non-renormalization theorem is proved to all orders in the weak coupling, showing that the usual criterion of minimizing the vacuum energy density is insufficient to determine the alignment, and possible resolutions of the problem are discussed. The second case is similar, except that the possible alignments are resricted to the range of Ω giving a vanishing VEV and the weak gauge group may then be broken non-minimally. In the third case, supersymmetry is itself broken at the tree level by the weak interactions. The supersymmetric generalization of the Schwinger mechanism for dynamical mass generation is described.     

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.     

Does there arise a significant enhancement of the dynamical quark mass in external magnetic field?

Recently, it was found in QED that the generation of a dynamical electron mass in a strong magnetic field is significantly enhanced by the perturbative electron mass. In the present Letter, the related question of a possible enhancement of the dynamical quark mass in an external magnetic field and with a bare mass term is investigated in the Nambu–Jona-Lasinio model.     

Energetics of the fission process

The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbersA225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) of the reaction and the Coulomb and deformation energy of the nascent fragments is shown to steer the characteristics of the fragment mass distributions.     

Some dynamical aspects of the fission process

The properties of the nuclear mass parameter and its influence on the fission process are discussed. In particular, correlations between dynamical and statical paths to fission are considered. The least action trajectories idea is used for finding the dynamical path to fission. Ritz method for the action integral minimalization is applied. An example of the nucleus ²⁵²Fm is considered.     

Conservation Laws for Partially Conservative Variable Mass Systems via d＇Alembert＇s Principle

Conservation laws for partially conservative variable mass dynamical systems under symmetric infinitesimal transformations are determined. A generalization of Lagrange-d ＇Alembert＇s principle for a variable mass system in terms of asynchronous virtual variation is presented. The generalized Killing equations are obtained such that their solution yields the transformations and the associated conservation laws. An example illusstrative of the theory is furnished at the end as well.     

Monte Carlo simulation of SU(2) Yang-Mills theory with light gluinos

In a numerical Monte Carlo simulation of SU(2) Yang-Mills theory with light dynamical gluinos the low energy features of the dynamics as confinement and bound state mass spectrum are investigated. The motivation is supersymmetry at vanishing gluino mass. The performance of the applied two-step multi-bosonic dynamical fermion algorithm is discussed. Received: 15 March 1999 / Published online: 22 October 1999     

On the dynamical vacuum rearrangement and the problem of fermion mass generation

We discuss the conditions under which the dynamical fermion mass generation mechanism may occur. The analogy between the vacuum rearrangement in massless electrodynamics, which results in the generation of a physical fermion mass, and the vacuum rearrangement concerned with the fall into the Coulomb centre with a large charge (Z > 137) is considered.     

Gauge independence and chiral symmetry breaking in a strong magnetic field

The gauge independence of the dynamical fermion mass generated through chiral symmetry breaking in QED in a strong, constant external magnetic field is critically examined. We present a (first, to the best of our knowledge) consistent truncation of the Schwinger-Dyson equations in the lowest Landau level approximation. We demonstrate that the dynamical fermion mass, obtained as the solution of the truncated Schwinger-Dyson equations evaluated on the fermion mass shell, is manifestly gauge independent.     

Homogeneous cosmological model for a Kaluza-Klein-type metric

Cosmological solutions are obtained for a homogeneous, spatially isotropic five-dimensional (5D) Kaluza-Klein-type metric with variable rest mass. The dynamical behavior of the model is studied and a comparison made with the corresponding solution in Einstein's 4D theory. Some important Cosmological parameters are also calculated for this model.     

Dynamical generation of topologically massive three-dimensional gauge fields and composite fermions

Phase transition, non-perturbative particle spectra including fermion-boson bound states and dynamical generation of topological gauge-invariant mass terms for the gauge fields in the general class of three-dimensional Higgs models with fermions are derived within the 1/N expansion.     

The Nambu-Jona-Lasinio mechanism of symmetry breaking in a U(5)-invariant model

We study dynamical symmetry breaking and mass generation in a U(5) four-fermion model with two coupling constants. We show that the consistency conditions result in a connection between the dynamical masses of the fermion quintuplet. The masses of fermions and of collective states are expressed through two independent quantities only. We find the propagator of the collective fields, from which it follows that there are goldstone fields as well as fields of massive particles. The mass formulas are obtained on the basis of dimensional regularization of divergent integrals.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 30–35, March, 1988.