[en] A spin glass (SG) phase was observed in the spin-density wave (SDW) alloys Cr_1-xCo_x at high Co concentrations (x≥13%). After zero-field cooling, the temperature dependence of the magnetization M(T) of Cr_0.87Co_0.13 and Cr_0.85Co_0.15, measured in an applied field H=100Oe with a SQUID magnetometer, exhibits a low T maximum, characteristic of a SG. Cooling in the measuring field, however, gives quite a different behavior. The field dependence of the magnetization M(H) is nonlinear, with a pronounced hysteresis. A strong time relaxation M(t) is also an indication of a SG phase. SG in Cr_1-xCo_x is formed at high impurity concentrations, possibly due to clustering of the magnetic impurities. [copyright] 2001 American Institute of Physics

No abstract available

[en] Methods for reconstructing the energy, event type, direction of motion, and injection point for electrons and muons in a water Cherenkov neutrino telescope similar to the SuperKamiokande detector are considered. The limiting resolutions estimated on the basis of an event simulation are compared with the values reported by the SuperKamiokande Collaboration

[en] The branching fractions of the semileptonic and rare B_s decays are calculated in the framework of the QCD-motivated relativistic quark model. The form factors of the weak B_s transitions are expressed through the overlap integrals of the initial and final meson wave functions in the whole accessible kinematical range. The momentum transfer dependence of the form factors is explicitly determined without additional model assumptions and extrapolations. The obtained results agree well with available experimental data

[en] The mass spectra of the ground state and excited heavy baryons consisting of two light (u, d, s) and one heavy (c, b) quarks are calculated. The heavy-quark-light-diquark picture is used within the relativistic quark model. An overall good agreement of the obtained predictions with available experimental data is found.

[en] The masses of the ground-state and excited heavy tetraquarks with hidden charm and bottom are calculated within the relativistic diquark-antidiquark picture. The dynamics of the light quark in a heavy-light diquark is treated completely relativistically. The diquark structure is taken into account by calculating the diquark-gluon form factor. New experimental data on charmonium-like states above the open charm threshold are discussed. The obtained results indicate that X(3872), Y(4260), Y(4360), Z(4433), and Y(4660) can be tetraquark states with hidden charm.

[en] The mass spectra of charmonia and bottomonia are calculated in the framework of the relativistic quark model up to high orbital and radial excitations. The Regge trajectories of heavy quarkonia are constructed both in the (J,M²) and (n_r,M²) planes, where J is the total angular momentum and nr is the radial quantum number. All daughter trajectories turn out to be almost linear and parallel, while parent trajectories exhibit some nonlinearity. Such nonlinearity occurs only in the vicinity of ground states and few lowest excitations and is more pronounced for bottomonia, while it is only marginal for charmonia. The obtained results are compared with available experimental data, and a possible interpretation of the new charmonium-like states above open charm production threshold is discussed

[en] The relativistic model of heavy tetraquarks is formulated within the diquark-antidiquark picture. The diquark structure is taken into account by the diquark-gluon form factor. New experimental data on charmonium-like states above open charm threshold are discussed. The obtained results indicate that X(3872), Y(4140), Y(4260), Y(4360), Z₂(4250), Z(4433) and Y(4660) could be tetraquark states with hidden charm. Predictions for the masses of bottom counterparts to the charm tetraquark candidates are given.

[en] The properties of light and heavy mesons, baryons and tetraquarks are discussed within a QCD-motivated relativistic quark model. The results for the mass spectra, electroweak properties and Regge trajectories of hadrons are presented.

[en] Properties of heavy and strange baryons are investigated in the framework of the relativistic quark-diquark picture. It is based on the relativistic quark model of hadrons, which was previously successfully applied for the calculation of meson properties. It is assumed that two quarks in a baryon form a diquark and baryon is considered as the bound quark-diquark system. The relativistic effects and diquark internal structure are consistently taken into account. Calculations are performed up to rather high orbital and radial excitations of heavy and strange baryons. On this basis the Regge trajectories are constructed. The rates of semileptonic decays of heavy baryons are calculated. The obtained results agree well with available experimental data.