2,223 research outputs found
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
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
We calculate the invariant and helicity amplitudes for the transitions
where the
are -type ground and excited states with
quantum numbers . 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
and the are
suppressed compared with those for the ground state
and the excited state . This analysis is
important for the identification of the hidden charm pentaquark states
and which were discovered in the decay chain
because the cascade decay chain
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 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
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