Radiative decays of ρ and ω mesons

The results of the measurements of radiative decays of ρ and ω mesons with the Neutral Detector at thee ⁺ e ^? collider VEPP-2M are presented. The branching ratio of the decay ω→π ⁰γ was measured with higher than in previous experiments accuracy: $${\rm B}(\omega \to \pi ^0 \gamma ) = 0.0888 \pm 0.0062$$ . The ρ⁰→π ⁰ γ branching ratio was measured for the first time: $$B(\rho ^0 \to \pi ^0 \gamma ) = (7.9 \pm 2.0) \cdot 10^{ - 4} $$ . The decays ρ, ω→ηγ were studied. Their branching ratios with the assumption of constructive ρ?ω interference are: $$\begin{gathered} B(\omega \to \eta \gamma ) = (7.3 \pm 2.9) \cdot 10^{ - 4} , \hfill \\ B(\rho \to \eta \gamma ) = (4.0 \pm 1.1) \cdot 10^{ - 4} \hfill \\ \end{gathered} $$ . The branching ratios of ρ, ω→ηγ and ω→e ⁺ e ^? decays were also measured: $$\begin{gathered} B(\omega \to \pi ^ + \pi ^ - \pi ^0 ) = 0.8942 \pm 0.0062, \hfill \\ B(\omega \to e^ + e^ - ) = (7.14 \pm 0.36) \cdot 10^{ - 5} \hfill \\ \end{gathered} $$ . The upper limit for the ω→π ⁰ π ⁰ γ branching ratio was placed: B(ω→π ⁰ π ⁰ γ)<4·10^?4 at 90% confidence level.     

Influence of Ionizing Radiation on the Properties of a Nanodispersed PdO/CeO<Subscript>2</Subscript> Catalyst in the Reaction of Low-Temperature Carbon Monoxide Oxidation

The effect of electron-beam irradiation on the catalytic properties of PdO/CeO₂ has been examined. It has been found that irradiation in the range of 15–30 kGy results in an increase in the concentration of the radical anion [O^?], thereby enhancing the catalytic activity of PdO/CeO₂.     

Heterogeneous doping of sulfide-conducting phases based on calcium and barium thiolanthanates

The chemical method of preparation of oxide precursors was used to obtain sulfide-conducting ionic salts of CaY₂S₄, BaSm₂S₄ and heterogeneous additives of ZrS₂ and SiS₂, accordingly. The sintering modes for obtaining the heterogeneous systems of CaY₂S₄–ZrS₂ and BaSm2S4–SiS2 were chosen. Samples were characterized using the methods of X-ray phase analysis and microprobe analysis. The methods of thermogravimetric and differential thermal analysis were used to determine thermal stability of samples. The temperature and concentration dependences of conductivity and average ionic transport numbers were studied. The range of compositions of heterogeneous mixtures is determined in which conductivity considerably exceeds conductivity of the basic sulfide-conducting solid electrolytes.     

Synthesis and thiocyanation of <Emphasis Type="Italic">N</Emphasis>-alkyl(trifluoromethyl)sulfonyl 1,4-benzoquinone monoimines

New N-alkyl(trifluoromethyl)sulfonyl 1,4-benzoquinone monoimines were synthesized, and their thiocyanation gave 5-alkyl(trifluoromethyl)sulfonylamino-1,3-benzoxathiol-2-ones. An intermediate thiocyanation product, 5-trifluoromethylsulfonylamino-1,3-benzoxathiol-2-imine, was isolated for the first time.     

<Emphasis Type="Italic">sym</Emphasis>-triazines. 8. Synthesis and some reactions of 4,6-disubstituted 2-(1H-pyrrolyl)-1,3,5-triazines

We have studied the reaction of 2,5-dimethoxytetrahydrofuran with 4,6-disubstituted 2-amino-1,3,5-triazines with the aim of obtaining novel coupled polyheterocyclic systems with potential bioactivity. Reaction conditions were optimized. A series of novel 4,6-disubstituted 2-(1H-1-pyrrolyl)-sym-triazines was obtained. It was found that the product yields depended on the nature of the substituent in the 4 and 6 positions of the triazine ring and on the reaction conditions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 440–451, March, 2008.     

Experimental study of the subthreshold production of K +-mesons in proton-nucleus collisions

Energy dependence of the differential cross sections for the production of K ⁺-mesons with a momentum of 1.28 GeV/c (c is the speed of light) by protons incident on Be, Al, Cu, and Ta nuclei was measured for energies both above and below the K ⁺-meson production threshold in pp collisions. Evidence is given for the dominance of the mechanism of direct production in the experiment. The characteristics of momentum distribution are determined for nucleons in the Be and Al nuclei up to 650 MeV/c. The data cannot be described in the model of nuclear spectral function.