Showing papers on "Explicit symmetry breaking published in 1985"
TL;DR: In this article, the symmetry breaking of E6 in low energy superstring theory was studied and a method for calculating the effective Higgs vacuum expectation values was presented, showing that there are theories with naturally light SU2w Higgs doublets and all theories in which this occurs.
204 citations
TL;DR: In this article, two models of this kind are presented and compared with a supersymmetric model, and two new models require modifications to the usual treatment of density fluctuations, which may be difficult to be achieved in practice.
150 citations
TL;DR: In this paper, a mean field approximation with the use of a QCD-motivated effective Lagrangian was proposed for chiral symmetry breaking and restoration in a system with zero temperature and zero chemical potential.
Abstract: Possible critical phenomena associated with chiral symmetry breaking and restoration are studied in the mean field approximation with the use of a QCD-motivated effective Lagrangian. Collective excitations in a system with zero temperature and zero chemical potential are examined extensively: It is shown that (i) there exists a precursory mode in the Wigner phase, which softens as the system approaches the critical point for chiral symmetry breaking, and (ii) the σ-meson mode in the Nambu-Goldstone (NG) phase softens being associated with symmetry restoration. The observabilities of these critical phenomena in experiment such as ultra-relativistic heavy ion collisions are discussed. We also calculate the critical temperature T_χ and critical chemical potential µ_χ where chiral symmetry gets restored and we obtain T_χ=164 MeV for (N_c=3, N_f=2)-case without free parameters.
112 citations
TL;DR: In this article, a new class of color and/or charge symmetry breaking vacua is shown to exist in models of particle physics based on N = 1 supergravity with a minimal low energy particle content.
75 citations
TL;DR: In this paper, different phases of QCD2(Nc) are discussed, and it is shown that in the weak coupling regime (Nc→∞, g2Nc = const, g ≈ mq) chiral symmetry breaking takes place, and 〈G 2 〉 = −2π ǫ n 2 c g 2 N c /12π sol1 2.
72 citations
TL;DR: In this paper, the Peccei-Quinn symmetry of supersymmetric theories coupled to N = 1 supergravity was investigated and the scale of soft supersymmetry breakings was found to be M PQ ∼M Planck × exp ( −4π λ 2 )∼10 8−12 GeV.
70 citations
TL;DR: In this paper, a simple interpretation of the decomposition of the densities of states in the classical mechanical limit according to the regular representation of the permutation group and under certain circumstances, the molecular symmetry group is presented.
Abstract: A simple interpretation of the decomposition of the densities of states in the classical mechanical limit according to the regular representation of the permutation group and—under certain circumstances—the molecular symmetry group is presented. The relationship between recent results on densities of states of a given point group symmetry species and previous results based upon the molecular symmetry group is established. Some restrictions are discussed as well as the definition and application of symmetry numbers for the densities of states and partition functions of nonrigid and rigid molecules and transition states.
60 citations
TL;DR: In this article, a variational method was used to find spontaneous symmetry breaking in the space of gaussian trial wave functionals, and it was shown that λφ 4 theory undergoes spontaneous symmetry-breaking.
51 citations
TL;DR: In this article, the effects of Coulomb and other isospin-nonconserving potentials on the Fermi matrix element were evaluated for the superallowed β-decays of 22 Mg, 34 Cl, and 34 Ar.
50 citations
TL;DR: In this paper, it was shown that the Dyson-Schwinger equation for massless quarks determines the asymptotic form of the chiral symmetry breaking part of the quark self-energy.
48 citations
TL;DR: A strongly interacting Higgs theory is considered and new sources of isospin-symmetry breaking are found; in particular there is one which contributes directly to the \ensuremath{\rho} parameter with strength that is linear in the effective Yukawa coupling of the heaviest ordinary fermion.
Abstract: The sensitivity of physical amplitudes to the observed isospin-symmetry breaking in the fermion mass matrix is analyzed in theories where the electroweak symmetry is dynamically broken. As a first step toward discussing dynamical theories in a model-independent way, we consider a strongly interacting Higgs theory. The nonlinear \ensuremath{\sigma} model coupled to an SU(2)\ifmmode\times\else\texttimes\fi{}U(1) Yang-Mills theory and to fermions is used to generate the low-dimensional operators induced by the quantum theory. The strengths of these operators, in particular those that break isospin symmetry, are estimated using the Higgs-boson mass of the linear \ensuremath{\sigma} model as a regulator. Technicolor models are next considered as a specific example of the strong-interaction physics which leads to electroweak symmetry breaking. Emphasis is placed on the effective four-fermion interactions that are natural partners of those which give mass to the ordinary fermions. New sources of isospin-symmetry breaking are found; in particular there is one which contributes directly to the \ensuremath{\rho} parameter with strength that is linear in the effective Yukawa coupling of the heaviest ordinary fermion. This effect is qualitatively different from the quadratic dependence found in Higgs theories.
TL;DR: In this article, spontaneous symmetry breaking in the presence of long range instantaneous interactions is studied and the general mechanism underlying it is clarified, and a characteristic feature is that the algebraic dynamics does not leave any essentially local algebra stable, i.e. variables at infinity get involved in the time evolution of local variables, so that in each irreducible representation the time Evolution fails to be symmetric.
Abstract: Spontaneous symmetry breaking in the presence of long range instantaneous interactions is studied and the general mechanism underlying it is clarified A characteristic feature is that the algebraic dynamics does not leave any essentially local algebra stable, ie variables at infinity get involved in the time evolution of local variables, so that in each irreducible representation the time evolution fails to be symmetric For continuous symmetries, the Fourier transform of the vacuum expectation value of charge commutators is related to the energy spectrum at low momenta and a generalized Goldstone theorem is proved which explains the generation of energy gap This energy gap is further shown to be governed by a “classical dynamics at infinity”, equivalently by the group generated by the effective Hamiltonian and the charge Explicit examples are discussed
TL;DR: The Hartree-Fock stability problem, its relationship to the broken symmetry solutions, and the implications for a molecular nuclear framework distortion are briefly reviewed in this paper, where the case where no nuclear network is available is considered.
Abstract: The Hartree–Fock stability problem, its relationship to the broken symmetry solutions, and the implications for a molecular nuclear framework distortion are briefly reviewed. The case where no nucl...
TL;DR: In this paper, the relativistic stellar configurations of two new equations of state (EOS) for neutron matter were analyzed by taking into account the more recent observational evidence, and the resulting EOS have been obtained by solving a general field theoretical model for nuclear interaction which contains many models studied in the literature as particular cases.
Abstract: We analyze the consequences on relativistic stellar configurations of two new equations of state (EOS) for neutron matter by taking into account the more recent observational evidence. The EOS have been obtained by solving a general field (Lagrangian) theoretical model for nuclear interaction which contains many models studied in the literature as particular cases. The model describes an assembly of nucleons interacting via scalar (sigma) mesons, pions (..pi..), and vector (..omega.. and rho) mesons; it is solved in the renormalized Hartree approximation, and the relativistic effects are included. The first resulting EOS (EOS I) comes from a particular determination of the free parameters in the Serot model, gives a satisfactory description of the saturation properties of symmetric nuclear matter and of the symmetry energy at nuclear density, and can be accurately matched to the Baym-Bethe-Pethick EOS at a density of approx.8 x 10/sup 12/ g cm/sup -3/. The nuclear incompressibility (460 MeV) is too high in this case. The second EOS (EOS II) comes from a determination of the free parameters of the linear sigma-model with an explicit symmetry breaking term and is coupled to the ..omega.. and rho mesons in a renormalizable way. This EOS reproduces accurately the propertiesmore » of symmetric nuclear matter at nuclear density and, in particular, gives a nuclear incompressibility of 225 MeV. We present the configurations which result when solving the general relativistic stellar structure equations with both EOS I and II and, for the sake of comparison, with the Chin and the so-called Canuto EOS. EOS I and II lead to equilibrium configurations compatible with the present status of observational evidence.« less
TL;DR: In this article, an explicit derivation of an effective action for composite operators is presented, which has the same local extrema as the effective action of Cornwall, Jackiw and Tomboulis.
TL;DR: In this article, the Parisi replica symmetry breaking scheme is considered for spin glass models without reflection symmetry (e.g. Potts glass, uniaxial quadrupolar glass).
Abstract: The Parisi replica symmetry breaking scheme is considered for spin glass models without reflection symmetry (e.g. Potts glass, uniaxial quadrupolar glass). It is shown that the retention of all the quartic terms in the free energy functional allows one to demonstrate the invalidity of naive applications of Parisi's scheme to such models.
TL;DR: In this article, the decomposition of the complete point symmetry model in a rectangular contingency table is shown, and the respective decompositions for the local and reverse local point symmetry models in a square contingency table are given.
Abstract: The decomposition for the complete point symmetry model in a rectangular contingency table is shown. Also the respective decompositions for the local point symmetry model and the reverse local point symmetry model in a square contingency table are given. Moreover test procedures for the decomposed models and an example are given.
TL;DR: In this paper, a simple variational principle for an O(2) invariant scalar theory, within the framework of gaussian wave functionals, is presented, and conditions for the occurrence of spontaneous symmetry breaking are discussed.
Journal Article•
TL;DR: In this paper, the authors discuss SU(5) breaking in models employing the missing multiplet mechanism to keep Higgs doublets light and show that 75 breaking can lead to numerous patterns of symmetry brealing, all with degenerate minima up to small gravitational corrections.
TL;DR: In this article, the authors discuss several aspects of gauged supersymmetric sigma-models: off-shell formulation, supersymmetry breaking and breaking of internal symmetry, and some specific examples are given.
TL;DR: The renormalization-group-improved theory for an m/sub r/not =0 (massive) QCD Lagrangian exhibits bifurcation in this limit, and chiral symmetry remains broken.
Abstract: We formulate the renormalization-group-improved theory for an m/sub r/not =0 (massive) QCD Lagrangian. The Green's functions are parametrized in terms of two renormalization-group--invariant quantities, M/sub 0/ and ..lambda../sub c/. The theory exhibits usual analyticity structure for every M/sub 0/>..lambda../sub c/e/sup 1/6/. In the limit M/sub 0/ = ..lambda../sub c/e/sup 1/6/, m/sub r/ becomes zero. The theory exhibits bifurcation in this limit, and chiral symmetry remains broken. is calculated in this limit.
TL;DR: Dirac operators are studied using nonrelativistic scattering theory in one higher dimension, and Abelian axial anomalies are examined using a generalization of Levinson's theorem to clarify the relations between instantons, fermion zero modes, and symmetry breaking.
Abstract: d-dimensional Dirac operators are studied using nonrelativistic scattering theory in one higher dimension, and Abelian axial anomalies are examined using a generalization of Levinson's theorem. The formalism is useful in the analysis of instanton-induced symmetry breaking, in particular when the computations must be performed on an open space. This is demonstrated by clarifying the relations between instantons, fermion zero modes, and symmetry breaking.
TL;DR: In this article, a simple mechanical system which exhibits spontaneous symmetry breaking similar to that appearing in a ferroelectric material is presented, which can be used to introduce the phase transition mechanism and related concepts such as universality classes and critical exponents in an elementary fashion.
Abstract: A very simple mechanical system which exhibits spontaneous symmetry breaking similar to that appearing in a ferroelectric material is presented. This model can be used to introduce the phase transition mechanism and related concepts such as universality classes and critical exponents in an elementary fashion. It can be easily understood by students of an introductory course in statistical physics.
TL;DR: In this paper, spontaneous symmetry breaking of the SO(10) symmetry was studied in the context of a six-dimensional Einstein-Yang-Mills theory based on SO(12).
TL;DR: In this article, the authors apply renormalization group equations that describe the finite-temperature behavior of Green's functions to investigate thermal properties of spontaneous symmetry breaking, and show that there always exists the unbroken symmetry phase at high temperature.
TL;DR: The structure of constrained Hamiltonian systems is investigated and the structure functions are shown to obey remarkable identities which ensure the existence of the Becchi-Rouet-Stora symmetry for any gauge theory.
Abstract: The structure of constrained Hamiltonian systems is investigated. The structure functions are shown to obey remarkable identities which ensure the existence of the Becchi-Rouet-Stora symmetry for any gauge theory. © 1985 The American Physical Society.
TL;DR: A purely geometric symmetry-breaking mechanism involving no free parameters is presented, in which the symmetry is broken by the higher-dimensional metric through Einstein's equation.
Abstract: The spontaneous symmetry breaking in higher-dimensional unified field theories is discussed in a general setting A purely geometric symmetry-breaking mechanism involving no free parameters is presented, in which the symmetry is broken by the higher-dimensional metric through Einstein's equation
TL;DR: It is shown that spontaneous breakdown of parity within left-right-symmetric theories can be entirely responsible for generating a spontaneous break down of "isospin" symmetry leading to large up-down mass splitting within a family.
Abstract: It is shown that spontaneous breakdown of parity within left-right-symmetric theories can be entirely responsible for generating a spontaneous breakdown of "isospin" symmetry leading to large up-down mass splitting within a family.