Beauty baryon production in pp collisions at LHC and b quark distribution in proton

The production of charmed and beauty hadrons in proton-proton collisions at high energies are analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. We present some predictions for the future experiments on the beauty baryon production in $pp$ collisions at LHC energies. This analysis allows us to find interesting information on the Regge trajectories of the heavy (b{\bar b}) mesons and the sea beauty quark distributions in the proton.Comment: 7 pages, 7 figures. Talk given at EDS'09: 13th International Conference on Elastic & Diffractive Scattering, CERN, Geneva, 29th June-3rd July, 200

Characterization of Bulk Nanostructural Bi2Te3-based Material Prepared by Microwave-solvothermal Synthesis and Hot Isostatic Pressure

The bulk nanostructural Bi2Te3-based material was prepared by microwave assisted solvothermal method and hot isostatic pressure. Optimal synthesis conditions of the Bi2Te3 nanopowder were found. It was established that hot isostatic pressing of the nanopowders at the temperature of 400 С and the pres-sures of 2, 4, 6 and 8 GPa allowed us to prepare the homogeneous and dense Bi2Te3-based material with the mean grain size of~50 nm. It is found that an electrical resistivity increases as the mean grain size of the material under study decreases. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3638

Theoretical description of the decays Λb→Λ(∗)(12±,32±)+J/ψ\Lambda_b \to \Lambda^{(\ast)}(\frac12^\pm,\frac32^\pm) + J/\psi

We calculate the invariant and helicity amplitudes for the transitions $\Lambda_b~\to~\Lambda^{(\ast)}(J^P)~+~J/\psi$ where the $\Lambda^{(\ast)}(J^P)$ are $\Lambda(sud)$-type ground and excited states with $J^P$ quantum numbers $J^P=\frac12^{\pm},\frac32^{\pm}$. The calculations are performed in the framework of a covariant confined quark model previously developed by us. We find that the values of the helicity amplitudes for the $\Lambda^\ast(1520,\,\frac32^-)$ and the $\Lambda^\ast(1890,\,\frac32^+)$ are suppressed compared with those for the ground state $\Lambda(1116,\,\frac12^+)$ and the excited state $\Lambda^\ast(1405,\,\frac12^-)$. This analysis is important for the identification of the hidden charm pentaquark states $P_c^+(4380)$ and $P_c^+(4450)$ which were discovered in the decay chain $\Lambda_b^0~\to~P_c^+(~\to~p~J/\psi)~+~K^-$ because the cascade decay chain $\Lambda_b~\to~\Lambda^\ast(\frac32^\pm)(~\to~pK^-)~+~J/\psi$ involves the same final state.Comment: 15 pages, 4 figures. Minor corrections don

Electrical Resistivity Peculiarities of the Nanograined Bi2Te3 Material

The hot quasiisostaic pressure method was applied to sinter the nanograined Bi2Te3 material. The samples with various mean grain size of 64, 61, 56 and 51 nm were prepared by changing the pressure of sintering. It was found that the specific electrical resistivity of the material under study increases when the mean grain size decreases. The Hall effect was measured to extract the concentration and mobility values of the charge carries. It was found that the electron concentration decreases as the mean grain size decreases while the electron mobility has extreme dependence on the grain size

Extended Rein-Sehgal model for tau lepton production

The polarization density matrix formalism is employed to include the final lepton mass and spin into the popular model by Rein and Sehgal for single pion neutrinoproduction. We investigate the effect of the $\tau$ lepton mass on the differential cross sections. The lepton polarization evaluated within the extended RS model is compared against that follows from the single resonance production model based upon the Rarita-Schwinger formalism with phenomenological transition form factors.Comment: Contribution to the 3rd International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region, 17-21 March, Gran Sasso (Italy

Linear Positive Magnetoresistivity of the Bi1.9Lu0.1Te3 Alloy with Inhomogeneous Micrograined Structure

Positive nonsaturating transverse magnetoresistivity (MR) has been observed below room temperature in the Bi1.9Lu0.1Te3 alloy with inhomogeneous micrograined structure. A crossover from parabolic MR ~ B2 dependence in low magnetic fields to linear MR ~ B dependence in high fields was found in the magnetoresistivity curves. The crossover field is shifted to lower magnetic fields as temperature decreases. Within the temperature range of “metal” type of conductivity, the temperature dependences of the specific electrical resistivity and MR magnitude are determined by the temperature dependence of the carrier mobility due to acoustic phonon scattering. Linear MR can be associated with microstructural inhomogeneity leading to strong electrical disorder of the Bi1.9Lu0.1Te3

Hopping Conductivity and Negative Magnetoresistance of the Bulk Nanograined Bi2Te3 Material

The bulk nanograined Bi2Te3 material was prepared by the microwave assisted solvothermal method and cold isostatic pressure method. It was found that above T* ≈ 190 K the temperature dependence of the specific electrical resistivity of material is of metallic type, while below this temperature a semiconductor conductivity takes place. Within the temperature ΔT ≈ 90 K-35 K interval the electrical conductivity of material can be described by the variable-range hopping conductivity mechanism. Negative magnetoresistance was observed at the same temperature interval

Microstructure and thermoelectric properties of Bi1.9Lu0.1Te3 compound

Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.1Te3 compound was studied. Starting nanopowder with mean nanoparticle size of *37 nm was synthesized by a microwave-solvothermal metho