New strong sector, odd-parity processes, and the Tevatron

The color-octet isosinglet "rho" of a new strong-interaction sector is readily produced in ppbar collisions. Its odd-parity decay to an "eta" and a gluon may exceed its decay rate to dijets. At center of mass energies sufficiently greater than the colored "rho" mass, the odd-parity production of ("omega" + colored "eta") or ("rho" + colored "pion") may be comparable to ttbar production. Considering that the "omega" has a dominant odd-parity decay mode, we end up with (Z, W, or gamma) + 4 jet events with two of the jets containing b or bbar.Comment: 8 pages, uuencoded PS file, try ghostscript or direct printing rather than ghostview, PS file of paper without figure is available on WWW at http://bigmac2.physics.utoronto.ca/BHpapers.htm

Emergent states in heavy electron materials

We obtain the conditions necessary for the emergence of various low temperature ordered states (local moment antiferromagnetism, unconventional superconductivity, quantum criticality, and Landau Fermi liquid behavior) in Kondo lattice materials by extending the two-fluid phenomenological theory of heavy electron behavior to incorporate the concept of hybridization effectiveness. We use this expanded framework to present a new phase digram and consistent physical explanation and quantitative description of measured emergent behaviors such as the pressure variation of the onset of local moment antiferromagnetic ordering at T_N, the magnitude of the ordered moment, the growth of superconductivity within that ordered state, the location of a quantum critical point, and of a delocalization line in the pressure/temperature phase diagram at which local moments have disappeared and the heavy electron Fermi surface has grown to its maximum size. We apply our model to CeRhIn_5 and a number of other heavy electron materials and find good agreement with experiment.Comment: 20 pages, 8 figures, 1 tabl

Simulation of patterns of crystallizing ingot macrostructure formation

The electromagnetic, hydrodynamic, and temperature fields of a crystallizing cylindrical ingot with a diameter of 163 mm have been calculated using the finite-difference method. Crystallization has been simulated in an electromagnetic crystallizer. The crystallization rate has been calculated, and then the ingot areas have been divided into small crystals, dendrites and globular ones. Quantitatively, the relationship between the temperature field gradient during crystallization and the ingot structure can be expressed by the following rules: 1) elongated grains of about 10 mm - cooling rate of about 1.8 • 10-4 kg/s; 2) elongated grains of about 20-30 mm - cooling rate of about 0.7 • 10-4-1.8 • 10-4 kg/s; 3) globular grains with a size of 10-20 mm - cooling rate of less than 0.7 • 10-4 kg/s. The possibility of simulation of the ingot structure during its crystallization based on the relationship between the crystallization rate and the grain size has been shown. The influence of the inductor current frequency on the structure of a crystallizing ingot has been simulated. It has been shown that an increase in the current frequency from 5 to 500 Hz leads to the expansion of the area with small crystals. © Published under licence by IOP Publishing Ltd

Influence of Rb, Cs and Ba on Superconductivity of Magnesium Diboride

Magnesium diboride has been thermally treated in the presence of Rb, Cs, and Ba. Magnetic susceptibility shows onsets of superconductivity in the resulting samples at 52K (Rb), 58K (Cs) and 45K (Ba). Room-temperature 11B NMR indicates to cubic symmetry of the electric field gradient at boron site for the samples reacted with Rb and Cs, in contrast to the axial symmetry in the initial MgB2 and in the sample treated with Ba.Comment: 3 pages (twocolumn), 2 figure

Field-induced quantum critical route to a Fermi liquid in high-temperature superconductors

In high transition temperature (T_c) superconductivity, charge doping is a natural tuning parameter that takes copper oxides from the antiferromagnet to the superconducting region. In the metallic state above T_c the standard Landau's Fermi-liquid theory of metals as typified by the temperature squared (T^2) dependence of resistivity appears to break down. Whether the origin of the non-Fermi-liquid behavior is related to physics specific to the cuprates is a fundamental question still under debate. We uncover a new transformation from the non-Fermi- to a standard Fermi-liquid state driven not by doping but by magnetic field in the overdoped high-T_c superconductor Tl_2Ba_2CuO_{6+x}. From the c-axis resistivity measured up to 45 T, we show that the Fermi-liquid features appear above a sufficiently high field which decreases linearly with temperature and lands at a quantum critical point near the superconductivity's upper critical field -- with the Fermi-liquid coefficient of the T^2 dependence showing a power-law diverging behavior on the approach to the critical point. This field-induced quantum criticality bears a striking resemblance to that in quasi-two dimensional heavy-Fermion superconductors, suggesting a common underlying spin-related physics in these superconductors with strong electron correlations.Comment: 6 pages, 4 figure

THE PROBLEM OF RUSSIAN POST-REVOLUTIONARY EMIGRATION IN THE CONTEXT OF THE INTERNATIONAL POSITION OF THE SOVIET STATE IN THE FIRST HALF OF THE 1920S

Aim. To consider the Soviet perception of Russian post-revolutionary emigration in the context of the key foreign policy challenges to the Soviet Country of the first half of the 1920s.Methodology. On the basis of the principles of historism and scientific objectivity, the authors analyzed a number of archival and official Soviet documents, as well as parts of the memoirs and journalistic heritage of the Russia Abroad related to the research.Results. It is concluded that during this period the Bolsheviks considered the post-revolutionary emigration as one of the biggest threats to the security of the young Soviet state.Research implications. The article introduced for the first time into the scientific circulation some archival documents that give a more detailed idea of the formation of the Soviet position regarding the plans of F. Nansen for a large-scale repatriation of Russian emigrants to their homeland in the 1920s.</html