The origin of the first and third generation fermion massesin a technicolor scenario

We argue that the masses of the first and third fermionic generations, which are respectively of the order of a few MeV up to a hundred GeV, originate from a dynamical symmetry breaking mechanism leading to masses of the order , where is a small coupling constant, and , in the case of the first fermionic generation, is the scale of the dynamical quark mass ( MeV). For the third fermion generation is the value of the dynamical techniquark mass ( GeV). We discuss how this possibility can be implemented in a technicolor scenario, and how the mass of the intermediate generation is generated.Received: 24 July 2003, Published online: 26 November 2003     

Information theory and the problem of molecular structure

Recently it has been shown that the classical stick and ball viewpoint of molecules is inconsistent with quantum theory (QT). We suggest an unusual reconciliation: The QT state is not a physical property, but instead reflects our state of knowledge about observable aspects of reality. We show how this perspective is nevertheless objective. Applied to molecules, the view permits structure to exist only when observable evidence is compatible with this feature. Typically one must replace the a priori model (in particular, the dynamical generator) with one consistent with the evidence. We show that such structure is stable in the context of first-order perturbation theory. We also indicate how dynamics can be inferred from scattering data—a process alternative to postulating (field-theoretic) models for environment.     

Effect of density-dependent nucleon-nucleon cross-section on elastic scattering

A linear form of density-dependent total nucleon-nucleon (NN) cross-section that depends on the coordinates of the projectile and target is applied in the Glauber phase shift formula. The only free parameter in these calculations is the density-dependent parameter , which is adjusted to obtain an agreement between the calculated angular distribution of the elastic-scattering cross-section and the corresponding experimental one. The elastic scattering of the ¹²C ion on the ¹²C ion target has been studied at incident energies of 300, 360, 1016, 1441 and 2400 MeV. The total reaction cross-section is also calculated with the obtained value of for the same reactions. The obtained values of are compared with those obtained from the optical-model analysis as well as those of the experimental value. Nuclear transparency effects are also discussed. Generally, the density-dependent NN cross-section improves the calculated results.Received: 11 February 2003, Revised: 8 July 2003, Published online: 26 January 2004PACS: 24.10.-i Nuclear-reaction models and methods - 25.70.-z Low and intermediate energy heavy-ion reactions     

B\bar B mixing with the bulk fields in the Randall-Sundrum model

We calculate mixing in the Randall-Sundrum bulk model. In this model, all the standard model fields except the Higgs field can reside in the bulk. Two suggestive models of mixed and relaxed scenarios are considered. We find that the enhancement of the loop function is 0.51% for the relaxed and 1.07% for the mixed scenario when the first four Kaluza-Klein modes are included, for a bulk fermion mass parameter .Received: 15 October 2003, Published online: 18 February 2004     

Noised-induced phase transition in an oscillatory system with dynamical traps

A new type of noised induced phase transitions is proposed. It occurs in noisy systems with dynamical traps. Dynamical traps are regions in the phase space where the regular forces are depressed substantially. By way of an example, a simple oscillatory system with additive white noise is considered and its dynamics is analyzed numerically. The dynamical trap region is assumed to be located near the x-axis where the velocity v of the system becomes sufficiently low. The meaning of this assumption is discussed. The observed phase transition is caused by the asymmetry in the residence time distribution in the vicinity of zero value velocity. This asymmetry is due to a cooperative effect of the random Langevin force in the trap region and the regular force not changing the direction of action when crossing the trap region.Received: 25 April 2003, Published online: 19 November 2003PACS: 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion - 05.45.-a Nonlinear dynamics and nonlinear dynamical systems - 05.70.Fh Phase transitions: general studies     

Form factors in the “point form” of relativistic quantum mechanics: Single- and two-particle currents

Electromagnetic and Lorentz-scalar form factors are calculated for a bound system of two spin-less particles exchanging a zero-mass scalar particle. Different approaches are considered including solutions of a Bethe-Salpeter equation, a point form approach to relativistic quantum mechanics and a non-relativistic one. The comparison of the Bethe-Salpeter results, which play the role of an experiment here, with the ones obtained in point form in single-particle approximation, evidences sizable discrepancies, pointing to large contributions from two-body currents in the latter approach. These ones are constructed using two constraints: ensuring current conservation and reproducing the Born amplitude. The two-body currents so obtained are qualitatively very different from standard ones. Quantitatively, they turn out not to be sufficient to remedy all the shortcomings of the point form form factors evidenced in impulse approximation.Received: 3 July 2003, Revised: 28 October 2003, Published online: 23 July 2004PACS: 11.10.St Bound and unstable states; Bethe-Salpeter equations - 13.40.Gp Electromagnetic form factors - 12.39.Ki Relativistic quark modelL. Theußl: Present address: TRIUMF, 4004 Wesbrook Mall, Vancouver, B.C., Canada, V6T 2A3     

Ordered structures and statistical properties of ion clouds stored in a Paul trap

A numerical investigation of the dynamics of ions forming small clouds confined in a Paul trap has been performed by means of a Monte-Carlo simulation. Inclusion of laser cooling results in crystallization of the trapped ions. The shape of ordered structures is predicted.     

Adsorption isotherms for fluids with strong interparticle repulsions

We derive adsorption isotherms for an adsorbate of hard-sphere particles with sticky interactions at any fluid density being adsorbed onto a plane, sticky surface. The theory is based on the Percus-Yevick theory for bulk fluids and explicitly includes the equilibrium between the adsorbed fluid and the bulk adsorbate. The theory predicts a surface condensation at low temperatures and low bulk densities in good agreement with surface condensations found in experimental studies of adsorption of gases onto graphite. An approximate law of corresponding states for these transitions is developed. At higher bulk densities and room temperatures, the adsorption isotherms can show a maximum, in accord with recent experimental work.Supported by the Australian Research Grants Commission.     

Raman effect of light on argon atoms

Scalar scattering of light on the 3p and 3s subshells of the argon atom (Stokes scattering) and anti-Stokes scattering on the excited 4p and 4s states of argon are examined in the Hartree-Fock approximation. The calculation is made in a velocity form and in a length form. It is shown that the value in the r form is 1.5–2 times greater than in the form.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 36–42, January, 1977.     

Third harmonics of the AC magnetic susceptibility: a method for the study of flux dynamics in high temperature superconductors

The temperature dependence of the 1st and 3rd harmonics ( ) of the AC magnetic susceptibility has been measured on melt grown YBCO samples for different frequencies and amplitudes of the AC magnetic field and intensity of a contemporaneously applied DC field. With the help of critical state models and of numerical simulations [22], we have devised a novel method, based on the combined analysis of the 1st and the 3rd harmonics (specifically on the comparison between and ), that allows to distinguish different temperature ranges dominated by the different dissipative magnetic flux regimes. In particular, we identified three principal zones in the temperature dependence of the real part of the 3rd harmonic: the zone 1, in the temperature range below the peak of the imaginary part of the 1st harmonic, , and the zone 2, characterized by negative values in a temperature region just above , both dominated by the creep regime; the zone 3, just below T _c , in which we revealed the presence of Thermally Assisted Flux Flow (TAFF). By the identification of these zones, an estimation of the value of the pinning potential can be obtained.Received: 23 September 2003, Published online: 19 November 2003PACS: 74.25.Ha Magnetic properties - 74.60.Ge Flux pinning, flux creep, and flux-line lattice dynamics     

Parametrization of the scattering indicatrix for a finite scattering medium

We consider a method of parametrizing the radiative scattering indicatrix. The scattering indicatrix is represented as projections , , on the axes of a Cartesian system of coordinates. Examples are discussed of the experimental determination of these parameters for a model dispersive medium consisting of a solution of polystyrene latex particles in water.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 36–39, October, 1985.     

First-order transitions in spherical models: Finite-size scaling

Finite-size behavior near the first-order phase boundary of ferromagnetic spherical models is investigated for block- and cylinder-shaped systems ind dimensions. The bulk thermodynamic singularities are rounded and, asymptotically for large size, obey appropriate scaling laws. Both short-range interactions and long-range couplings, decaying like 1/r^d+ with >0, are analyzed: the short-range results agree precisely with a recently developed scaling theory forO(n) symmetric systems in the limitn. More generally, the scaling functions are universal, depending only on . Explicit aspects of the shape and interactions enter only in the spin wave or Goldstone mode contributions which appear, technically, as corrections to scaling. An appendix analyzes the truncation error in the approximation, by many-fold sums, of multivariate integrals with integrands diverging like [_ja_{j j} ² ]^- as 0.     

Quasi-free \pi^0 photoproduction from the bound nucleon

Differential cross-sections for quasi-free photoproduction from the proton and neutron bound in the deuteron have been measured for MeV at using the Glasgow photon tagger at MAMI, the Mainz 48 cm cm NaI(Tl) photon detector and the Göttingen SENECA recoil detector. For the proton measurements made with both liquid-deuterium and liquid-hydrogen targets allow direct comparison of free photoproduction cross-sections as extracted from the bound-proton data with experimental free cross-sections which are found to be in reasonable agreement below 320 MeV. At higher energies the free cross-sections extracted from quasi-free data are significantly smaller than the experimental free cross-sections and theoretical predictions based on multipole analysis. For the first time, free neutron cross-section have been extracted in the -region. They are also in agreement with the predictions from multipole analysis up to 320 MeV and significantly smaller at higher photon energies.Received: 28 May 2003, Published online: 27 January 2004PACS: 13.60.Le Meson production - 14.20.Dh Protons and neutrons - 25.20.Lj Photoproduction reactionsK. Kossert: Part of the Doctoral Thesis.,Present address: Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany.Present address F. Wissmann: Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany. Present address B. Seitz: II. Physikalisches Institut der Universität Gießen, Germany.     

Diffuse optical harmonic generation in SiC nanopowder films: hunting scattered photons

Second- and third-harmonic generation in polymer films doped with silicon carbide nanopowders is experimentally studied in the regime of weak scattering, with the size of nanoparticles a, the elastic scattering length l, the radiation wavelength , and the film thickness L meeting the relations alL. The strong wavelength dependence of diffuse second- and third-harmonic generation observed under these conditions indicates a significant role of scattering effects in nonlinear optical interactions in nanopowder materials, which allows diffuse harmonic generation to be controlled by varying the ratio of the characteristic size of the nanoparticles to the wavelength of the pump radiation. The contribution of scattering-delayed pump photons to diffuse third-harmonic generation in a SiC nanopowder film is visualized by measuring the third-harmonic intensity as a function of the delay time between two pump pulses. PACS 42.65.Ky; 42.25.Dd; 61.46.+w     

Excitation of adsorbed molecule vibrations in low energy electron scattering

We develop a theory of low energy electron loss spectroscopy of vibrational modes of molecules adsorbed on metal surfaces. Differential and total cross sections are calculated in the Distorted Wave Born Approximation, assuming i) strong elastic scattering on the metal surface, ii) direct electron-molecule interaction via the electric dipole field associated with the molecular vibration. The angular distributions are calculated and discussed for molecules adsorbed at various distances above the metal surface and for several electron energies and impact angles. The influence of electronic screening of dipolar oscillations is discussed and the consequences of the classical induced image dipoles are explored. It is shown that the metal surface selection rule known in IR spectroscopy is only approximately valid in electron scattering. Finally, we give numerical estimates of the inelastic scattering cross sections for the stretching vibrations of CO molecule adsorbed on transition metal surfaces, in reasonable agreement with experiments.     

Acoustomagnetoelectric current effects on mesoultrasound in anisotropic semiconductors

The acoustomagnetoelectric (AME) current effects on mesoultrasound in monopolar single-valley semiconductors with anisotropic scattering in arbitrary classical magnetic fields are computed analytically. The specimen is considered short-circuited along the q-wave vector of the ultrasound (US) wave. Two configurations are examined: 1) q is directed at an arbitrary angle 9 to the axis of highest order crystal symmetry C₆ (z axis), the y axis to the (q, C₆) plane, the magnetic field B lies in the (q, y) plane at an arbitrary angle to the vector q. Two transverse AME field components are calculated: along y and in the (q, C₆) plane. They express the Hall effects at mesoultrasound, the planar and normal, 2) q is directed along the y axis while B is in the (x, z) plane at an angle to the C₆(z) axis. The AME field component along B, the Grobner effect at mesoultrasound, is calculated. The dependence of the effects onB is studied and their estimate is given in weak and strong fields.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 57–61, July, 1989.     

Spectral‐Luminescent Properties of 1,1‐Dioctadecyl‐3,3,3'3'‐Tetramethylindodicarbocyanineperchlorate in Binary Solutions

On the basis of investigation of the absorption and luminescence spectra of 1,1dioctadecyl3,3,3'3'tetramethylindodicarbocyanineperchlorate (D307) molecules and their nonamphiphilic analog in binary solutions of dimethylformamide and water of different composition, a mechanism underlying the quenching luminescence of the D307 molecules has been established which is related to the formation of nonluminescent associates. It is shown that the formation of the micelles of sodium dodecylsulfate (SDS) in a binary solution with 99% content of water destroys the associates, the D307 molecules are captured by the micelles, and their mobility in the micelles is limited.     

Coherent production of pairs of parabosons of order 2

A parameter-free statistical model is used to study multiplicity signatures for coherent production of charged pairs of parabosons of order p = 2 in comparison with those arising in the case of ordinary bosons, p = 1. Two non-negative real parameters arise because ab and ba are fundamentally distinct pair operators of charge + 1, A-quanta and charge -1, B-quanta parabosons. In 3D plots of the probability of m paraboson charged pairs + q positive parabosons versus and , the p = 1 curve is found to lie on the relatively narrow 2D p = 2 surface.Received: 26 December 2003, Published online: 21 December 2004     

Photostability of Molecules of Aromatic Amines in a Polymeric Matrix

In the temperature range T = 5–295 K, the spectralluminescent properties and curves of thermostimulated luminescence (TSL) of molecules of triphenylamine (TPA), trirtolylamine (TTA), triranisolamine (TAA), and N,N'diphenylbis(3methylphenyl)(1,1'biphenyl)4,4'diamine (TPD) in polystyrene and 4Brpolystyrene matrices have been investigated. It has been found that photoirradiation at room temperature in the region of the lowest electron transition of molecules leads to a decrease in the intensities of the luminescence, photoluminescence, and TSL bands, as well as to the formation of new deep traps for charge carriers. At equal irradiation doses these changes in TPD are noticeably less pronounced than in TPA, TTA, and TAA. The higher photochemical stability of TPD molecules compared to TPA, TTA, and TAA is attributed to the difference in the mechanisms of nonradiative deactivation of the triplet states of molecules.     

Is the strong-interaction proton-proton scattering length renormalization scale dependent in effective field theory?

It is shown that the strong-interaction ¹S₀ proton-proton scattering length in very low-energy effective field theory does not depend on the renormalization scale, if the electromagnetic interaction is switched off consistently.Received: 3 July 2003, Revised: 26 September 2003, Published online: 20 January 2004PACS: 03.65.Nk Scattering theory - 13.75.Cs Nucleon-nucleon interactions (including antinucleons, deuterons, etc.)