[en] The processes γγ->μ⁺μ^-e⁺e^- and γγ->e⁺e^-e⁺e^- with polarized photons are studied in detail. They are the most suitable processes for determining the luminosity of high-energy γγ colliding beams. Completely differential, inclusive and total cross sections as well as energy spectra are calculated. All the distributions depend only on the linear photon polarizations. In the single muon inclusive cross section polarization effects may reach 19%. The application of our results to QCD multi-jet production in γγ collisions is briefly discussed. (orig.)

[en] Aluminium iodate octahydrate monocrystals have been synthesized. Chemical composition of the substance is refined using the methods of chemical and thermal analyses, roentgenography and density measurement. Parameters of triclinic unit cell are determined: a=7.467(1), b=8.389(1), c=13.567(2) A; α=88.96(1), β=87.66(1), γ=63.58(1) deg; d_calcld=3.066, d_exp=3.04 g/cm³. Powder pattern of Al(IO₃)₃x8H₂O is identified

[en] It is shown that if the a₀(980) and f₀(975) mesons are the four-quark (q²anti q²) states then they must be produced intensively enough in the decays Φ→π⁰ηγ and Φ→ππγ, respectively, Br(Φ→γa₀→π⁰ηγ) = 2.0x10^-4 and Br(Φ→γf₀→ππγ) = 2.6x10^-4. In the case of their two-quark (qanti q) nature the decay intensity is an order of magnitude less at least. That is why the experimental study of the Φ→π⁰ηγ and Φ→ππγ decays allows essential advancement towards the solution of the question about the four-quark nature of the a₀(980) and f₀(975) resonances. (orig.)

No abstract available

[en] The Stark effect in a crystal field is considered for crystals with rare-earth ions R of the type Lasub(1-x)Rsub(x)Z,Lusub(1-x)Rsub(x)Z or RZ. The shift in the crystal-field levels with temperature due to phonon interactions is computed. The computations differ from earlier ones since the crystal symmetry is used, and the results are expressed in terms of observable thermodynamic quantities for crystals of the LaZ, LuZ type. (author)

[en] The resonance type enhancement discovered recently near the γγ → K^*0anti K^*0 reaction threshold is explained by the one-kaon Regge exchange. The problem of the experimental extraction of the reactions γγ → ωω, γγ → K^*0anti K^*0, γγ → ρ⁰φ is discussed. It is shown that there are no grounds to use the t-channel factorization model for the explanation of the near threshold enhancement in the reaction γγ → ρ⁰ρ⁰. The reactions which can be used to search for the exotic state in the ρ⁺ρ⁺, ρ^-ρ^- and ρ^±ρ⁰ channels are pointed out. (orig.)

[en] A possibility of the Dirac-Schwinger point heavy-mass monopoles detection in scattering or production of photons at large angles via the monopole loop, is discussed. The monopoles with masses M < or approximately from 50 to 100 GeV may be found in experiments at PETRA and PEP, and monopoles with masses M < or approximately from 2 to 3 TeV may be discovered in future experiments in colliding photon beams of 50-300 GeV energies

[en] Short note. 1 ref

[en] The corrections to the thermal properties of crystals which contain rare-earth ions are computed. These corrections arise from magnetoelastic interaction. It is shown that different thermal properties contain the same free parameters and hence fitting must be done simultaneously. (author)

[en] Using the method of polarization-optical observations, the sequence of phase transitions in monocrystals RbLiMoO₄ is studied. The change in the crystal twinning pattern in plates of cross sections (100) and (110) points to the following sequence of symmetry exchange in RbLiMoO₄: anti 43m(V₀) → 3m(V₀) → mm2(2V₀) → m(2V₀) at 423, 406 and 393 K respectively