Moscow State University

About: Moscow State University is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Catalysis & Laser. The organization has 66747 authors who have published 123358 publications receiving 1753995 citations. The organization is also known as: MSU & Lomonosov Moscow State University.

Quasi-elastic electroproduction of charged \rho -mesons on nucleons

Abstract: The electroproduction of charged $ \rho$ -mesons on the nucleon at intermediate energy is discussed for quasi-elastic kinematics. It is shown that at these kinematics both the longitudinal $ \sigma_{{L}}^{}$ and transverse $ \sigma_{{T}}^{}$ cross-sections are dominated by the $ \rho$ -meson t -pole contribution, and thus the corresponding dσL(T)/dt data can give a valuable information on the $ \rho$ -meson component of the nucleon cloud. The differential cross-sections for the reaction p(e, e ′ $ \rho^{+}_{}$ )n at Q 2 = 2 , 3.5GeV^2 and at the invariant mass W = 3 and 4GeV are calculated on the basis of quasi-elastic knockout mechanism with form factors. Questions about the gauge invariance of the electroproduction amplitude are considered and it is noted an important difference between photo- and electroproduction amplitudes.

Conical emission from laser plasma interactions in the filamentation of powerful ultrashort laser pulses in air.

Abstract: We performed detailed experimental and numerical investigations of the conical emission (CE) accompanying the filamentation of powerful ultrashort laser pulses in air. It was found that the CE originates from self-phase modulation in the plasma produced by the pulse during propagation. The experiment and the simulation agree on the essential features of the CE: The CE angle decreases with increasing wavelength and is independent of the position along the filament, and there is no CE at Stokes-shifted wavelengths.

Photonic band gap phenomenon and optical properties of artificial opals

Abstract: We report on the photonic band gap phenomenon in the visible range in a three-dimensional dielectric lattice formed by close-packed spherical silica clusters. The spectral position and the spectral width of the optical stop band depend on the direction of light propagation with respect to the crystal axes of opal, and on the relative cluster-to-cavity refraction index n. Manifestations of the photonic pseudogap have been established for both transmission and emission spectra. The stop band peak wavelength shows a linear dependence on n. Transmission characteristics of the lattice have been successfully simulated by numerical calculations within the framework of a quasicrystalline approximation. @S1063-651X~97!13805-3#