Spontaneous breakdown of the gauge chiral symmetry and the cabibbo angle

From the general treatment of the spontaneous breakdown of the chiral SU(3)xSU(3) group down to the electromagnetic U(l) gauge group it is conjectured that the bare Cabibbo angle isπ/4. Imposing the self-consistency condition of Cabibbo and Maiani on the weak and electromagnetic corrections to the chiral symmetry breaking Hamiltonianh=ε₀ u ₀+ +ε₃ u ₃+ε₈ u ₈ leads to the determination of the physical Cabibbo angle. The agreement with the experimental value is reached when the parametrization ofh of Brandt and Preparata is used.     

Spontaneous symmetry breakdown and Regge intercepts

By Regge slope methods we exhibit a Nambu-Goldstone spontaneous symmetry breakdown and a Higgs mechanism inherent in a unit-intercept dual meson amplitude. Introducing an Abelian gauge group corresponding to conservation of a pseudocharge, Regge intercept shifts are calculated; to lowest order the leading Regge intercept of the Neveu-Schwarz model is lowered from $\text{α(0) = 1}\text{to}\text{α(0) =}\text{1}\text{2}$. Our method has the advantage over Bardakci's spurion method that massless scalar are not required at any stage.     

Progress in hypernuclear physics

The recent progress in hypernuclear physics is discussed in this paper. The topics include recent results on hypernuclear gamma-ray spectroscopy, non-mesonic weak decay, and double- hypernuclei. Future prospects at the 50 GeV PS are also discussed.Received: 30 September 2002, Published online: 22 October 2003PACS: 21.80. + a Hypernuclei - 25.80.-e Meson- and hyperon-induced reactions     

FINUDA,a hypernuclear physics experiment

FINUDA is a hypernuclear physics experiment to be held from the summer of 2002. The hypernuclear physics program and the apparatus characteristics and performances are here reviewed.     

Spontaneous symmetry breakdown and boson condensation in biology

Electric polarization waves predicted by Frölich in living cells are identified as the Goldstone massless modes which appear as a consequence of the spontaneous breakdown of the SU(2) dipole-rotational symmetry. This breaking is provided by the water polarization induced by Davydov solitons travelling on molecular chains.     

Spontaneous breakdown of CP in left right symmetric models

We show that it is possible to obtain spontaneous CP violation in the minimal SU(2)_L × SU(2)_R × U(1)_{B -L}, i.e. in a left right symmetric model containing a bidoublet and two triplets in the scalar sector. For this to be a natural scenario, the non-diagonal quartic couplings between the two scalar triplets and the bidoublet play a fundamental role. We analyze the corresponding Higgs spectrum, the suppression of FCNC’s and the manifestation of the spontaneous CP phase in the electric dipole moment of the electron.     

Spontaneous violation of CP symmetry in the strong interactions

Some time ago Dashen [Phys. Rev. D 3, 1879 (1971)] pointed out that spontaneous CP violation can occur in the strong interactions. I show how a simple effective Lagrangian exposes the remarkably large domain of quark mass parameters for which this occurs. I close with some warnings for lattice simulations.     

Spontaneous symmetry breakdown in the abelian Higgs model

For the abelian Higgs model we introduce a new gauge invariant observable which in Landau gauge is . In three or more dimensions this observable is used to show that the global gauge symmetry is spontaneously broken in the lattice theory for a suitable range of parameters. This observable also provides a gauge invariant order parameter for the phase transition in this model.Research supported by U.S. National Science Foundation grant PHY8116101-A03Research supported by U.S. National Science Foundation grant PHY8117463     

Spontaneous symmetry breakdown and symmetry restoration in the statistical mechanics of a many-boson model

We study the statistical mechanics of a many-boson system with constant two-body potential energy g/N (g > 0, N is the number of bosons). The grand canonical partition function can be computed exactly by functional integration which allows for a simple discussion of spontaneous symmetry breakdown. It turns out to be possible to exhibit the healing of the broken symmetry.     

Spontaneous symmetry breakdown in the standard dual string model

The problem of spontaneous symmetry breakdown in the standard dual string model is solved. The propagator of the resulting new model is determined, and the absence of the tachyon from the spectrum is demonstrated.     

Spontaneous translation symmetry breakdown for quantum lattice systems

We study the set of equilibrium states for quantum lattice states in the presence of a translation symmetry of the model. We derive a characterization of the spontaneous breaking of this symmetry, i.e., the decomposition of an invariant equilibrium state into a mixture of noninvariant equilibrium states, in terms of the separability in mean energy of these states for a class of perturbed dynamics.     

Absence of breakdown of continuous symmetry in two-dimensional models of statistical physics

Two-dimensional lattice model is considered. The connected Lie groupG acts on a configuration space. The Gibbs potential assumed to be invariant under this action. We prove, that under general assumption on the potential, each Gibbs random field with this potential is alsoG-invariant.     

Spontaneous symmetry breakdown: Analogies and differences between superconductivity,quantum chromodynamics,and quantum flavordynamics

The dynamical theory of spontaneous breakdown correctly predicts the bound states and relates the order parameters of electron-phonon superconductivity and quark-gluon chiral symmetry. A similar statement cannot be made for the standard electroweak gauge symmetry.     

Spontaneous CP violation in a Z4 horizontal symmetry model for flavor mixing

The implications of a Z₄ horizontal symmetry model of flavor mixing for CP violation are studied in the framework of minimal SU(2)_L × SU(2)_R × U(1)_{B – L} gauge theory. We show that CP violation in this model arises purely from right-handed currents. We also note that spontaneous breaking of CP symmetry requires a fine tuning of coupling parameters to the level of , which can be avoided by the inclusion of one additional singlet Higgs field, of the kind recently introduced for other purposes.     

Flavour physics and CP violation

It is well known that the study of flavour physics and CP violation is very important to critically test the Standard Model and to look for possible signature of new physics beyond it. The observation of CP violation in kaon system in 1964 has ignited a lot of experimental and theoretical efforts to understand its origin and to look for CP violation effects in other systems besides the neutral kaons. The two B-factories BABAR and BELLE, along with other experiments, in the last decade or so made studies in flavour physics and CP violation a very interesting one. In this article we discuss the status and prospectives of the flavour physics associated with the strange, charm and bottom sectors of the Standard Model. The important results in kaon sector will be briefly discussed. Recently, mixing in the charm system has been observed, which was being pursued for quite some time without any success. The smallness of the mixing parameters in the charm system is due to the hierarchical structure of the CKM matrix. Interestingly, so far we have not found CP violation in the charm system but in the future, with more dedicated experiments at charm threshold, the situation could change. Many interesting observations have been made in the case of bottom mesons and some of them show some kind of deviations from that of the Standard Model expectations which are mainly associated with the b → s flavour changing neutral current transitions. It is long believed that the B _s system could be the harbinger of new physics since it is a system in which both bottom and strange quarks are the constituents. Recently, D0 and CDF announced their result for the B _s mixing which is claimed to be the first possible new physics signature in the flavour sector. We plan to touch upon all important issues pointing out both theoretical and experimental developments and future prospects in this review article.