Concerning CP violation in 331 models

We consider the implementation of CP violation in the context of 331 models. In particular we treat a model where only three scaler triplets are needed in order to give all fermions a mass while keeping neutrino massless. In this case all CP violation is provided by the scalar sector.

A model for Hopfions on the space-time S(3)xR

We construct static and time dependent exact soliton solutions for a theory of scalar fields taking values on a wide class of two dimensional target spaces, and defined on the four dimensional space-time S-3 X R. The construction is based on an ansatz built out of special coordinates on S3. The requirement for finite energy introduce boundary conditions that determine an infinite discrete spectrum of frequencies for the oscillating solutions. For the case where the target space is the sphere S-2, we obtain static soliton solutions with nontrivial Hopf topological charges. In addition, such Hopfions can oscillate in time, preserving their topological Hopf charge, with any of the frequencies belonging to that infinite discrete spectrum. (C) 2005 American Institute of Physics.

Integral equations of scattering in one dimension

A self-contained discussion of integral equations of scattering is presented in the case of centrally symmetric potentials in one dimension, which will facilitate the understanding of more complex scattering integral equations in two and three dimensions. The present discussion illustrates in a simple fashion the concept of partial-wave decomposition, Green's function, Lippmann-Schwinger integral equations of scattering for wave function and transition operator, optical theorem, and unitarity relation. We illustrate the present approach with a Dirac delta potential. (C) 2001 American Association of Physics Teachers.

Transition amplitudes for the nonmesonic hypernuclear decay

We give general expressions for the two-body decomposition of the transition amplitudes for the nonmesonic decay of Lambda-hypernuclei within a finite-nucleus shell-model approach.

Expansion effects on back-to-back correlations

The back-to-back correlations (BBC) of particle-antiparticle pairs, signalling in-medium mass modification, are studied in a finite size thermalized medium. The width of BBC function is explicitly evaluated in the case of a nonrelativistic spherically symmetric expanding fireball. The effect of the flow is to reduce the BBC signal as compared to the case of non flow. Nevertheless, a significant signal survives finite-time emission plus expansion effects.

L-R asymmetries and signals for new bosons

Several left-right parity violating asymmetries in lepton-lepton scattering in fixed target and collider experiments are considered as signals for doubly charged vector bosons (bileptons).

Modeling of organic light-emitting diodes with graded concentration in the emissive multilayer

We model the electrical behavior of organic light-emitting diodes whose emissive multilayer is formed by blends of an electron transporting material, tris-(8-hydroxyquinoline) aluminum (Alq(3)) and a hole transporting material, N,N-'-diphenyl-N,N-'-bis(1,1(')-biphenyl)-4,4-diamine. The multilayer is composed of layers of different concentration. The Alq(3) concentration gradually decreases from the cathode to the anode. We demonstrate that these graded devices have higher efficiency and operate at lower applied voltages than devices whose emissive layer is made of nominally homogeneous blends. Our results show an important advantage of graded devices, namely, the low values of the recombination rate distribution near the cathode and the anode, so that electrode quenching is expected to be significantly suppressed in these devices. (C) 2004 American Institute of Physics.

QCD vacuum topology and glueballs

We outline a comprehensive study of spin-0 glueball properties which, in particular, keeps track of the topological gluon structure. Specifically, we implement (semi-hard) topological instanton physics as well as topological charge screening in the QCD vacuum into the operator product expansion (OPE) of the glueball correlators. A realistic instanton size distribution and the (gauge-invariant) renormalization of the instanton contributions are also implemented. Predictions for 0(++) and 0(-+) glueball properties are presented.

Simple derivation of general Fierz-type identities

General Fierz-type identities are examined and their well-known connection with completeness relations in matrix vector spaces is shown. In particular, I derive the chiral Fierz identities in a simple and systematic way by using a chiral basis for the complex 4 X 4 matrices. Other completeness relations for the fundamental representations of SU(N) algebras can be extracted using the same reasoning. (c) 2005 American Association of Physics Teachers.

Coulomb gauge quark model, vacuum condensates and high density quark matter

We consider here a Coulomb gauge quark model which includes an explicit construct for a nontrivial vacuum structure in QCD at finite density. Non-perturbative renormalization of ultraviolet diverges is performed by adding counterterms. The equation of state for u and d quark matter at zero temperature is calculated in the Hartree-Fock approximation.

Analysis of the Hb(b)over-bar coupling constant and CP-violation effects at the future e(+)e(-) collider

The e(+)e(-)-->b (B) over bar nu(ν) over bar process, where nu is an electron, muon, or tau-lepton neutrino, is analyzed in detail for the general form of the coupling constant of a Higgs boson with b quarks, with the (m(b)/v)(a + igamma(5)b) parameterization of the Hb (b) over bar interaction. This process is shown to be highly sensitive to this coupling constant. Experiments at the future with roots = 500-GeV linear collider will provide limits of 2 and 20% for deviations of the parameters a and b, respectively, from their Standard Model values. Results concerning the e(+)e(-)-->b (b) over bar nu(ν) over bar process in combination with the independent measurements of the partial width Gamma(H --> b (b) over bar) can testify to the CP origin of the Higgs sector of the theory. (C) 2003 MAIK Nauka/Interperiodica.

Plethysms and interacting boson models

A short review of the plethysm technique aiming to its application in finding branching rules for the reduction of an irreducible representation of a group under the restriction to one of its subgroups is given. The algebraic structure of the interacting boson model and some of its extensions is given together with the branching rules needed to classify their basis states, obtained by the use of plethysms. (C) 2003 American Institute of Physics.

Investigation of the H tau tau and Hbb coupling constants for a scalar (Pseudoscalar) higgs Boson at a future linear electron-positron collider

The possibility of setting constraints on the Couplings of a scalar (pseudoscalar) Higgs boson to the tau lepton and the b quark in the reactions e(+)e(-)-->v (v) over bar tau(+)tau(-) and e(+)e(-)-->v (v) over barb (b) over bar at a future linear electron-positron collider of total energy roots = 500 GeV is studied. The admixture of a new hypothetical pseudoscalar state of the Higgs boson in the Hf (f) over bar vertex is parametrized in the form (mf/v)(a+igamma(5)b). on the basis of an analysis of differential distributions for the processes under study, it is shown that data from the future linear collider TESLA will make it possible to constrain the parameters a and b as -0.32 less than or equal to Deltaa less than or equal to 0.24 and -0.73 less than or equal to b less than or equal to 0.73 in the case of the reaction e(+)e(-)-->v (v) over bar tau(+)tau(-) and as -0.026 less than or equal to Deltaa less than or equal to 0.027 and -0.23 less than or equal to b less than or equal to 0.23 in the case of the reaction e(+)e(-) --> v (v) over barb (b) over bar. It is emphasized that the contribution of the fusion Subprocess WW --> H in the channel involving an electron neutrino is of particular importance, since this contribution enhances the sensitivity of data to the parameters being analyzed. (C) 2004 MAIK Nauka/Inierperiodica.

Hadronic current correlation functions at finite temperature in the NJL model

Recently there have been suggestions that for a proper description of hadronic matter and hadronic correlation functions within the NJL model at finite density/temperature the parameters of the model should be taken density/temperature dependent. Here we show that qualitatively similar results can be obtained using a cutoff-independent regularization of the NJL model. In this regularization scheme one can express the divergent parts at finite density/temperature of the amplitudes in terms of their counterparts in vacuum.

The possibility of discovering new boson in e(-)e(-), mu(-)mu(-), e(-)mu(-) colliders

Several left-right asymmetries in Moller (electron-electron), muon-muon and electron-muon scattering are considered in the context of the electroweak standard model and in a model with SU(3)(C) x SU(3)(L) x U(1)(Y) gauge symmetry at tree level in collider experiments. We show that these asymmetries are very sensitive to a doubly charged vector bilepton in the case of ee and mu mu colliders and to an extra Z' neutral vector boson contribution in e(-)mu (-) collider.