Showing papers on "Explicit symmetry breaking published in 1977"
258 citations
TL;DR: In this article, a discrete flavor symmetry is proposed which leads to the relation tan 2 θ c = m d m s, where c is the number of flavors in the relation.
187 citations
15 Oct 1977
TL;DR: In this article, it was shown that for highly symmetric molecules the ionization of a core electron leads quite generally to a lowering of the symmetry, and that the breaking of symmetry is a consequence of the vibronic coupling between nearly degenerate core orbitals of different symmetry.
Abstract: It is shown that for highly symmetric molecules the ionization of a core electron leads quite generally to a lowering of the symmetry. The breaking of the symmetry is a consequence of the vibronic coupling between nearly degenerate core orbitals of different symmetry. The vibronic coupling leads to strong excitation of non-totally symmetric vibrational modes in addition to the usually observed excitation of totally symmetric modes. As an example, the vibrational structure of the Ols line of the CO 2 molecule is computed on the one-particle level.
123 citations
TL;DR: In this paper, the change in the Fermi matrix element due to deviations from perfect analogue symmetry has been estimated in a single-particle model with both harmonic oscillator and Saxon-Woods radial wave functions.
88 citations
CERN1
TL;DR: In this article, the authors show the occurrence of chiral symmetry breaking as a result of local fluctuations in the winding number, and they mainly restrict their discussion to QED2 in order to have an independent check of their methods from the known solution of this model.
74 citations
TL;DR: In this article, a supersymmetric theory with generalized kinetic and nonderivative interaction terms is found for the scalar supermultiplet coupled to supergravity, and symmetry breakdown and the super-Higgs effect are studied.
Abstract: We present results on the scalar supermultiplet coupled to supergravity. A locally supersymmetric theory with generalized kinetic and nonderivative interaction terms is found. We discuss a number of examples. Symmetry breakdown and the "super-Higgs" effect are studied, as is a consistent truncation of the SO(4) extended theory. Finally, we find the local extension of supersymmetric massless QED and discuss symmetry breakdown in this system.
60 citations
TL;DR: In this article, the formation of the site-symmetrized multipole expansion for the 32 crystal point symmetries is shown, and mutual relations between the real and reciprocal space expansions are discussed.
Abstract: Significance of symmetry in representing real- and reciprocal-space properties of a crystal and of its constituents is discussed in terms of symmetry eigenfunctions. The formation of the site-symmetrized multipole expansion for the 32 crystal point symmetries is shown, and the mutual relations between the real- and reciprocal-space expansions are discussed. The origin of the symmetry-based phase relations, equivalences and extinction rules of structure amplitudes is pointed out. Distinction is made between the accurate and approximate ones arising from the true space-group symmetry and from the approximate free-particle symmetry of the constituents, respectively. Finally, the symmetry imposed by reality of charge density and its violation through anomalous dispersion are discussed in terms of symmetric and antisymmetric contributions of atomic charge densities.
59 citations
TL;DR: In this paper, it was shown that the long-range forces arising on symmetry restoration need not lead back to an anisotropic, inhomogeneous, or domain-structure universe.
Abstract: The vacuum energy density now is small or zero but must have been prodigious if the universe was once hotter than ${T}_{c}\ensuremath{\sim}{10}^{15}$ K and if elementary-particle symmetry is spontaneously broken by a Higgs mechanism. If symmetry is broken nondynamically, in the hot disordered phase the huge vacuum energy density is nevertheless negligible, compared to the energy density of ultrarelativistic particles. Because the broken symmetry is non-Abelian, the long-range forces arising on symmetry restoration need not lead back to an anisotropic, inhomogeneous, or domain-structure universe.
55 citations
TL;DR: In this paper, a systematic study of symmetry breaking in nonrelativistic quantum mechanics of a scalar and a spinor particle is presented, where the free Schrodinger equation is invariant under the Euclidean group E(3); an external field will break this symmetry to a lower one.
Abstract: A systematic study of explicit symmetry breaking in the nonrelativistic quantum mechanics of a scalar and a spinor particle is presented. The free Schrodinger (or Pauli) equation is invariant under the Euclidean group E(3); an external field will break this symmetry to a lower one. We first find all continuous subgroups of E(3) and then for each subgroup construct the most general (within certain restrictions) external field that breaks the symmetry from E(3) to the corresponding subgroup. For a scalar particle the interaction term is assumed to be of the form V (r)+A(r)P, where P is the momentum, i.e., it involves an arbitrary scalar and vector potential. For a spinor particle it is of the form V (r)+A(r)P +B(r) σ+Mik(r) σiPk (σi are the Pauli matrices). A one‐to‐one correspondence between subgroups of E(3) and classes of ’’symmetry breaking potentials’’ is established. The remaining subgroup symmetry is then used to solve or at least simplify the obtained Schrodinger equation. The existence of a one‐dim...
48 citations
TL;DR: In this article, the O(N) invariant Goldstone field theory in two dimensions was studied and it was shown that for computation of the ground state energy at weak coupling it is still the standard Goldstone perturbation expansion that is applicable.
29 citations
TL;DR: In this paper, the concept of gauge symmetries of solutions to the Yang-Mills-Higgs field equations and the implications of such symmetry for the corresponding linear perturbation equations are discussed.
TL;DR: In this article, the isospin mixing of the lowest two 1 + states in 12 C is considered and a nuclear charge symmetry breaking interaction (CSB) was fitted to help explain the Nolen-Schiffer anomaly, but not as important as in the N-S problem.
TL;DR: In this paper, the authors propose a dressing mechanism of the basic field by which fields with particle interpretation are generated: an asymmetric dressing that relies strongly on the asymmetry of the ground state and a symmetric dressing which is only triggered by it.
Abstract: Spontaneous breakdown of a symmetry group in a dynamical theory is connected with a rearrangement of group properties between quantized and classical degrees of freedom enforced by the classical asymmetry properties of the ground state. By disentangling the classical and quantized parts in the original basic field operators, designed for describing the short-distance behaviour, and by rearranging them in various ways, new dressed field operators with different symmetry properties, adapted to the description in the asymptotic region, can be constructed which, in general, admit more appropriate linearizations of the theory and hence offer better starting points for a perturbative treatment of the interaction. There are essentially two different dressing mechanisms of the basic field by which fields with particle interpretation are generated: an asymmetric dressing which relies strongly on the asymmetry of the ground state and a symmetric dressing which is only triggered by it. The formalism is exemplified for the nonlinear chiral model of Nambu and Jona-Lasinio. The main purpose of the paper, however, does not aim at improving the approximations in this model, but is thought of as a preparation for a similar treatment of more realistic theories with a spontaneous breakdown of a non-Abelian symmetry group and of the dilatation group in which these considerations may offer natural explanations for the occurrence of approximate higher symmetries and for the mysterious coexistence of two types of particles, the leptons and gauge particles on the one hand and the hadrons on the other hand.
TL;DR: In this paper, it was shown that the presence of massless non-Goldstone bosons in the tree approximation is necessary both for the continuous case (gauge hierarchies involving pseudophotons) and for the discrete case, but not sufficient.
Abstract: We ask if it is possible for spontaneous symmetry breakdown to occur stepwise. The presence of massless non-Goldstone bosons in the tree approximation is necessary both for the continuous case (gauge hierarchies involving "pseudophotons") and for the discrete case, but it is not sufficient. Our findings on additional constraints are presented in the form of theorems. The first (concerning pseudophotons) depends only on the validity of perturbative expansions and on the Goldstone theorem. The other two require that all massless non-Goldstone bosons in the tree approximation arise from a vacuum symmetry.
TL;DR: In this paper, it was shown that in the mean-field approximation at T = 0 °K, the symmetry breaking increases with increasing density, and the state of dense matter and the early universe are shortly discussed.
TL;DR: In this paper, the sigma model with additional symmetry-breaking terms which are bilinear in meson fields is studied and the meson masses and meson decay constants are treated as functions of xi, the ratio of SU(3) octet to singlet vacuum symmetry breaking is analyzed.
Abstract: We have studied the sigma model with additional symmetry-breaking terms which are bilinear in meson fields. The meson masses and meson decay constants are treated as functions of xi, the ratio of SU(3) octet to singlet vacuum symmetry breaking. We find that all bilinear-symmetry-breaking models except one are not smooth in xi. This nonsmoothness arises because in some cases, M/sub S/..pi.. and M/sub S/K-italic, and in one case c, the ratio of SU(3) octet to singlet explicit symmetry breaking, becomes imaginary. The model in which solutions are smooth does not predict F/sub K//F/sub ..pi../ in the experimental range.
TL;DR: In this paper, simple expressions for the first-order redundancy coefficients in vibrational problems involving atoms with four bonds are given for the general case of no local symmetry and the specialization to Oh, C3v, and Cs symmetry.
TL;DR: In this paper, the authors define two statistical measures of symmetry breaking which take all the internal moments of the irreducible subspaces into account, and can be used in the ground state region of nuclei.
Abstract: We define two statistical measures of symmetry breaking which take all the internal moments of the irreducible subspaces into account, and can be used in the ground state region of nuclei. We test their validity in an exactly solvable model.
TL;DR: The problem of explicit supersymmetry breaking in a simple fermion-number-conserving model is discussed in this article, mainly in the context of a simple FPN model.
Abstract: The problem of explicit supersymmetry breaking is discussed, mainly in the context of a simple fermion-number-conserving model.
TL;DR: In this article, a microscopic investigation in a self-consistent particle-hole model reveals approximate unitary analog states in spite of large symmetry breaking, and the K-nucleus elastic scattering and (K −, π − ) excitation of these states are studied, showing strong surface effects.
TL;DR: A particularly interesting outcome of this hidden symmetry is the possibility of spin-zero leptons, which could be responsible for the anomalous eμ events seen in e+e−annihilation, as recently proposed by Ma, Pakvassa and Tuan.
20 Jun 1977