2,296 research outputs found
A potential including Heaviside function in 1+1 dimensional hydrodynamics by Landau
In 1+1 dimensional hydrodynamics originally proposed by Landau, we derive a
new potential and distribution function including Heaviside function and
investigate its mathematical and physical properties. Using the original
distribution derived by Landau, a distribution function found by Srivastava et
al., our distribution function, and the Gaussian distribution proposed by
Carruthers et al., we analyze the data of the rapidity distribution on charged
pions and K mesons at RHIC energies (sqrt(s_NN) = 62.4 GeV and 200 GeV). Three
distributions derived from the hydrodynamics show almost the same chi-squared
values provided the CERN MINUIT is used. We know that our calculations of
hadron's distribution do not strongly depend on the range of integration of
fluid rapidity, contrary to that of Srivastava et al. Finally the roles of the
Heaviside function in concrete analyses of data are investigated
Little IIB Matrix Model
We study the zero-dimensional reduced model of D=6 pure super Yang-Mills
theory and argue that the large N limit describes the (2,0) Little String
Theory. The one-loop effective action shows that the force exerted between two
diagonal blocks of matrices behaves as 1/r^4, implying a six-dimensional
spacetime. We also observe that it is due to non-gravitational interactions. We
construct wave functions and vertex operators which realize the D=6, (2,0)
tensor representation. We also comment on other "little" analogues of the IIB
matrix model and Matrix Theory with less supercharges.Comment: 17 pages, references adde
Angle-resolved photoemission spectroscopy of Co-based boride superconductor LaCo1.73Fe0.27B2
We have performed angle-resolved photoemission spectroscopy of Co-based
boride superconductor LaCo1.73Fe0.27B2 (Tc = 4.1 K), which is isostructural to
the 122-type Fe-pnictide superconductor with the pnictogen atom being replaced
with boron. We found that the Fermi level is located at a dip in the density of
states (DOS) in contrast to Co-pnictide ferromagnets. This reduction in DOS
together with the strong Co 3d-B 2p covalent bonding removes the ferromagnetic
order and may cause the superconductivity. The energy bands near the Fermi
level show higher three dimensionality and a weaker electron-correlation effect
than those of Fe pnictides. The Fermi surface topology is considerably
different from that of Fe pnictides, suggesting the difference in the
superconducting mechanism between boride and pnictide superconductors.Comment: 5 pages, 4 figure
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