425 research outputs found
Spin-Spin Asymmetries in Large Transverse Momentum Higgs Boson Production
We examine the spin-dependence of standard model Higgs boson production at
large transverse momentum via the processes , , and . The partonic level
spin-spin asymmetries () for these processes are large at SSC/LHC
energies.Comment: 10 pages, 4 figures (not included), LaTeX; PSU/TH/113, MAD/PH/70
Collapsing Layers on Schwarzschild-Lemaitre Geodesics
We discuss Israel layers collapsing inward from rest at infinity along
Schwarzschild-Lemaitre geodesics. The dynamics of the collapsing layer and its
equation of state are developed. There is a general equation of state which is
approximately polytropic in the limit of very low pressure. The equation of
state establishes a new limit on the stress-density ratio.Comment: To appear in Phys. Rev. D 1
Radiation and String Atmosphere for Relativistic Stars
We extend the Vaidya radiating metric to include both a radiation field and a
string fluid. Assuming diffusive transport for the string fluid, we find new
analytic solutions of Einstein's field equations. Our new solutions represent
an extention of Xanthopoulos superposition.Comment: To appear in Phys. Rev. D, Rapid Communicatio
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Evidence of Annealing Effects on a High-Density Si/SiO2 Interfacial Layer
Thermally grown Si(001)/SiO samples were studied by x-ray reflectivity. Fits of model electron density profiles to the data reveal the existence of an interfacial layer at the Si/SiO interface up to 15-Å-thick, with density higher than either the crystalline Si or the main oxide layer. This density of the layer is reduced by a postoxidation anneal.Engineering and Applied Science
Understanding the complex phase diagram of uranium: the role of electron-phonon coupling
We report an experimental determination of the dispersion of the soft phonon
mode along [1,0,0] in uranium as a function of pressure. The energies of these
phonons increase rapidly, with conventional behavior found by 20 GPa, as
predicted by recent theory. New calculations demonstrate the strong pressure
(and momentum) dependence of the electron-phonon coupling, whereas the
Fermi-surface nesting is surprisingly independent of pressure. This allows a
full understanding of the complex phase diagram of uranium, and the interplay
between the charge-density wave and superconductivity
Levi-Civita cylinders with fractional angular deficit
The angular deficit factor in the Levi-Civita vacuum metric has been
parametrized using a Riemann-Liouville fractional integral. This introduces a
new parameter into the general relativistic cylinder description, the
fractional index {\alpha}. When the fractional index is continued into the
negative {\alpha} region, new behavior is found in the Gott-Hiscock cylinder
and in an Israel shell.Comment: 5 figure
Solution generating with perfect fluids
We apply a technique, due to Stephani, for generating solutions of the
Einstein-perfect fluid equations. This technique is similar to the vacuum
solution generating techniques of Ehlers, Harrison, Geroch and others. We start
with a ``seed'' solution of the Einstein-perfect fluid equations with a Killing
vector. The seed solution must either have (i) a spacelike Killing vector and
equation of state P=rho or (ii) a timelike Killing vector and equation of state
rho+3P=0. The new solution generated by this technique then has the same
Killing vector and the same equation of state. We choose several simple seed
solutions with these equations of state and where the Killing vector has no
twist. The new solutions are twisting versions of the seed solutions
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Mechanisms of heavy-ion induced gate rupture in thin oxides
Single event gate rupture (SEGR) is a catastrophic failure mode that occurs in dielectric materials that are struck by energetic heavy ions while biased under a high electric field condition. SEGR can reduce the critical electric field to breakdown to less than half the value observed in normal voltage ramp reliability tests. As electric fields in gate oxides increase to greater than 5 MV/cm in advanced MOS technologies, the impact of SEGR on the reliability of space based electronics must be assessed. In this summary, the authors explore the nature of SEGR in oxides with thickness from 7 nm to less than 5 nm, where soft breakdown is often observed during traditional reliability tests. They discuss the possible connection between the present understanding of SEGR and voltage stress breakdown models
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