Leading twist contribution to color singlet χc0,2→ωω\chi_{c0,2}\to\omega\omega decays

In this paper the leading twist contribution to $\chi_{c0,2}\to\omega\omega$ decays in the color singlet approximation is considered. It is shown, that the predictions for \Br(\chi_0\to\omega\omega) is in a good agreement with the experimental data, while \Br(\chi_{c2}\to\omega\omega) differs from the experiment significantly.Comment: 4 pages, RevTeX; minor changes, some refrences adde

Gain limits of a Thick GEM in high-purity Ne, Ar and Xe

The dependence of the avalanche charge gain in Thick Gas Electron Multipliers (THGEM) on the purity of Ne, Ar and Xe filling gases was investigated. The gain, measured with alpha-particles in standard conditions (atmospheric pressure, room temperature), was found to considerably drop in gases purified by non-evaporable getters. On the other hand, small N2 admixtures to noble gases resulted in high reachable gains. The results are of general relevance in the operation of gas-avalanche detectors in noble gases, particularly that of two-phase cryogenic detectors for rare events.Comment: 15 pages, 6 figures, submitted to JINS

The first light of Mini-MegaTORTORA wide-field monitoring system

Here we describe the first light of the novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA, which is being tested now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (~900 square degrees) or narrow (~100 square degrees) fields of view, either in clear light or with any combination of color (Johnson B, V or R) polarimetric filters installed, with exposure times ranging from 100 ms to 100 s. The primary goal of the system is the detection of rapid -- with sub-second characteristic time-scales -- optical transients, but it may be also used for studying the variability of the sky objects on longer time scales.Comment: 9 pages, 9 figures, based on the talk presented on "Modern stellar astronomy-2014" (Rostov-on-Don

Non-sequential double ionization below laser-intensity threshold: Anticorrelation of electrons without excitation of parent ion

Two-electron correlated spectra of non-sequential double ionization below laser-intensity threshold are known to exhibit back-to-back scattering of the electrons, viz., the anticorrelation of the electrons. Currently, the widely accepted interpretation of the anticorrelation is recollision-induced excitation of the ion plus subsequent field ionization of the second electron. We argue that another mechanism, namely simultaneous electron emission, when the time of return of the rescattered electron is equal to the time of liberation of the bounded electron (the ion has no time for excitation), can also explain the anticorrelation of the electrons in the deep below laser-intensity threshold regime. Our conclusion is based on the results of the numerical solution of the time-dependent Schr\"{o}dinger equation for a model system of two one-dimensional electrons as well as an adiabatic analytic model that allows for a closed-form solution.Comment: 6 pages and 3 figure

Composition, Structure and Tribotechnical Properties of TiN, MoN Single-Layer and TiN/MoN Multilayer Coatings

Results of comprehensive investigations of nanostructed TiN and MoN single layer coatings as well as multilayer coatings consisting of TiN/MoN alternating layers have beenconsidered. The coatings have been deposited by a promising modern method of cathode-arc evaporation (vacuum-arc method). The elemental and phase compositions of coatings, their tribological and physico mechanical properties: friction coefficient, wear, adhesion, hardness, and elastic modulus have been studied and the mechanisms of the coatings fracture have been discussedyesBelgorod State Universit