Cohomological structure of the conformal anomaly

A cohomological classification of conformal anomalies in the dimension D=6 is given. Different anomaly classes have a common origin from the cohomological standpoint, being equivalent to the Euler density E₆. The descent equation technique is developed for conformal anomalies by analogy with gauge theories. All highest cocycles of the Weyl group are investigated. The general technique for constructing all conformal anomalies from the Weyl density E_2n in arbitrary space-time dimensions is presented. The principal difference between structures of these anomalies in dimensions D=4 and D=6 is demonstrated. A conformally invariant operator (constructed from Riemann and Ricci tensors, scalar curvature, and covariant derivatives) acting on a scalar with zero conformal weight is absent in D=6. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 117, No. 3, pp. 351–363, December, 1998.     

Spectroscopic study of polycrystalline TiO2 doped with vanadium

The structure of coordination sites (V⁴⁺ ions) and their spatial distribution in the polycrystalline titanium dioxide (rutile) lattice were studied by ESR. It was found that at low degrees of doping, at [V⁴⁺] < 0.5 at.%, the vanadium ions are isotropically distributed in the rutile lattice. At [V⁴⁺] > 0.5 at.% a new microphase with the mixed composition {TiO₂—VO²} is formed. The mixed microphase has a noticeably narrower band gap than the initial TiO₂. Comparison of the photocurrent spectra and the plots of the integral photocurrent vs. vanadium content with the structural data obtained using ESR spectroscopy showed that the formation of the {TiO₂—VO²} microphases deteriorates the photoelectrochemical properties of the modified photoelectrodes. Synthetic procedures interfering the formation of such microphases in the doped rutile are discussed.     

Resolving Controls for the Boundary Approximate Controllability of Sandwich Beams with Uncertainties the Green’s Function Approach

Mechanics of Composite Materials - The boundary approximate null-controllability of an Euler–Bernoulli sandwich beam subjected to a dynamically active distributed load is considered. The...     

Production of strange secondaries in high-energy Σ<Superscript>−</Superscript><Emphasis Type="Italic">A</Emphasis> collisions

The WA89 Collaboration experimental data on production of Λ, Σ⁻, Σ⁺, Ξ⁻, Ω⁻ baryons, $ \bar \Lambda $ \bar \Lambda and $ \bar \Xi ^ + $ \bar \Xi ^ + antibaryons in Σ⁻ collisions with C and Cu targets at 345 GeV/c ($ \sqrt {s_{\Sigma N} } $ \sqrt {s_{\Sigma N} } ≈ 25.5 GeV) in the frame of the Quark-Gluon String Model is described. The comparison of the theoretical results with the experimental data is discussed. Finally, some relations among the values of the model parameters obtained with the help of quark combinatorics are presented.     

D,D* (2010) and $D_{2}^{⇒t}(2460)$ charmed meson production in hadron—hadron collisions

A recently developed generalization of the Quark Gluon String Model to the case of bosonic resonance production in hadron—hadron collisions is used for the calculation of inclusive production of charmed mesons D, D*(2010) and $D_{2}^{?t}(2460)$. A simple relation which determines the depende2nce of the charmed meson production cross sections on their spin J is obtained. It is shown that the theoretical predictions for the inclusive spectra and production cross sections of these charmed mesons are confirmed experimentally with a reasonable accuracy.     

Ion-Pair Version of the Chemo- and Regioselectivity of Halogen Addition to Double Bond

Analysis of the stereoselectivity of halogenation of alkenes shows that the notion of the reaction intermediate as a three-membered halogenium state is contrary to fact. It is assumed that the precursors of the halogenation products are the ion pairs formed by step heterolysis of the C = C bond. This allows a logical connection to be revealed between the electronic properties of substituents in substrates and reagents, on the one hand, and the overall stereoselectivity and direction of halogenation, on the other.     

Description of πp→Δ(1232)π and πp→Δ(1232)ρ(770) reaction proceeding via baryon exchange mechanism

We analyze the available experimental data on the backward production processes N and N in the framework of the strong-cut Reggeized absorption model, which is based on the exchange of the baryon Regge trajectoriesN and with the associated cuts. The model describes rather well the data on the differential cross sections at incident momenta ranging from 2.15 to 20 GeV/c. An essential contribution of exchange even at small energies (E _lab of the order of a few GeV) is found. A model-independent analysis of data confirms this fenomena.     

Peculiarities of dislocation motion in aluminum with allowance for the Peierls relief in the presence of ultrasound

Physics of the Solid State - The effect of ultrasound on motion of the Frenkel–Kontorova dislocations in aluminum has been studied with inclusion of the Peierls relief. A dislocation moves at...     

Lienard-Wiechert potentials and synchrotron radiation from a relativistic spinning particle in pseudoclassical theory

For a relativistic spinning particle with an anomalous magnetic moment, Lienard-Wiechert potentials are constructed within the pseudoclassical approach. Some specific cases of the motion of a spinning particle are considered on the basis of general expressions obtained in this study for the Lienard-Wiechert potentials. In particular, the intensity of the synchrotron radiation from a transversely polarized particle moving along a circle at a constant speed is investigated as a function of the particle spin. In the specific case of particles having no anomalous magnetic moment and moving in an external uniform magnetic field, the resulting expressions coincide with familiar formulas from the quantum theory of radiation. The spin dependence of the polarization of synchrotron radiation is investigated.