5,730 research outputs found
Prospects for Mirage Mediation
Mirage mediation reduces the fine-tuning in the minimal supersymmetric
standard model by dynamically arranging a cancellation between anomaly-mediated
and modulus-mediated supersymmetry breaking. We explore the conditions under
which a mirage "messenger scale" is generated near the weak scale and the
little hierarchy problem is solved. We do this by explicitly including the
dynamics of the SUSY-breaking sector needed to cancel the cosmological
constant. The most plausible scenario for generating a low mirage scale does
not readily admit an extra-dimensional interpretation. We also review the
possibilities for solving the mu/Bmu problem in such theories, a potential
hidden source of fine-tuning.Comment: 14 page
Comment on ``Damping of energetic gluons and quarks in high-temperature QCD''
Burgess and Marini have recently pointed out that the leading contribution to
the damping rate of energetic gluons and quarks in the QCD plasma, given by
, can be obtained by simple arguments obviating the need
of a fully resummed perturbation theory as developed by Braaten and Pisarski.
Their calculation confirmed previous results of Braaten and Pisarski, but
contradicted those proposed by Lebedev and Smilga. While agreeing with the
general considerations made by Burgess and Marini, I correct their actual
calculation of the damping rates, which is based on a wrong expression for the
static limit of the resummed gluon propagator. The effect of this, however,
turns out to be cancelled fortuitously by another mistake, so as to leave all
of their conclusions unchanged. I also verify the gauge independence of the
results, which in the corrected calculation arises in a less obvious manner.Comment: 5 page
Universal Torsion-Induced Interaction from Large Extra Dimensions
We consider the Kaluza-Klein (KK) scenario in which only gravity exists in
the bulk. Without the assumption of symmetric connection, the presence of brane
fermions induces torsion. The result is a universal axial contact interaction
that dominates those induced by KK gravitons. This enhancement arises from a
large spin density on the brane. Using a global fit to Z-pole observables, we
find the 3 sigma bound on the scale of quantum gravity to be 28 TeV for n=2. If
Dirac or light sterile neutrinos are present, the data from SN1987A increase
the bound to \sqrt{n}M_S >= 210 TeV.Comment: 9 pages REVTeX, 1 postscript figure, uses axodraw.st
Evaporative Deposition Patterns Revisited: Spatial Dimensions of the Deposit
A model accounting for finite spatial dimensions of the deposit patterns in
the evaporating sessile drops of colloidal solution on a plane substrate is
proposed. The model is based on the assumption that the solute particles occupy
finite volume and hence these dimensions are of the steric origin. Within this
model, the geometrical characteristics of the deposition patterns are found as
functions of the initial concentration of the solute, the initial geometry of
the drop, and the time elapsed from the beginning of the drying process. The
model is solved analytically for small initial concentrations of the solute and
numerically for arbitrary initial concentrations of the solute. The agreement
between our theoretical results and the experimental data is demonstrated, and
it is shown that the observed dependence of the deposit dimensions on the
experimental parameters can indeed be attributed to the finite dimensions of
the solute particles. These results are universal and do not depend on any free
or fitting parameters; they are important for understanding the evaporative
deposition and may be useful for creating controlled deposition patterns.Comment: 34 pages, 14 figures, LaTeX; submitted to Physical Review
Computer Microscopy of Biological Fluid Dry Patterns for Medical Diagnostics
We elaborate hardware and software system that implements the principle of diagnosis based on the standard procedure of pattern preparation including digital recognition of image and its computer analysis based on specially developed algorithms by comparing with the expert descriptors and extensive database of dry pattern samples obtained from clinical treatments which include more than 1500 samples to high selective and accuracy recognition of pathologies, for recognition of wide range of pathologies, in particular, the endogenous intoxication.
Keywords: biological fluids, image analysis, medical diagnostics, endogenous intoxication
On the Quantum Inverse Problem for the Closed Toda Chain
We reconstruct the canonical operators of the quantum closed Toda
chain in terms of Sklyanin's separated variables.Comment: 16 page
Commensurate structural modulation in the charge- and orbitally-ordered phase of the quadruple perovskite (NaMn)MnO
By means of synchrotron x-ray and electron diffraction, we studied the
structural changes at the charge order transition =176 K in the
mixed-valence quadruple perovskite (NaMn)MnO. Below we
find satellite peaks indicating a commensurate structural modulation with the
same propagation vector q =(1/2,0,-1/2) of the CE magnetic order that appears
at low temperature, similarly to the case of simple perovskites like
LaCaMnO. In the present case, the modulated structure
together with the observation of a large entropy change at gives
evidence of a rare case of full Mn/Mn charge and orbital order
consistent with the Goodenough-Kanamori model.Comment: Accepted for publication in Phys. Rev. B Rapid Communication
Changes in Arctic Ocean Climate Evinced through Analysis of IPY 2007–2008 Oceanographic Observations
Full-depth hydrographical surveys conducted in 2007–2009 during the International Polar Year (IPY) collaboration provide an accurate snapshot of the Arctic Ocean (AO) hydrography at a time when the Arctic Ocean Oscillation (AOO) index was highest in recent record. We construct pan-Arctic temperature and salinity (T/S) reference states from these data using variational optimal interpolation and discuss some key differences between the 2007–2009 state and a similarly constructed climatology from historical 1950–1994 Russian archives. These data provide a recent, known reference state for both qualitative and quantitative future AO climate change studies. Furthermore, we present an analysis of sea-surface height (SSH) and upper-layer circulation constructed from the IPY data via 4DVar data assimilation and use them to examine circulation and freshwater source changes visible during IPY
- …