2,245 research outputs found
Improved thermal paint formulation
Potassium silicate-treated zinc oxide paint stabilizes pigment against ultraviolet-induced, bleachable degradation in infrared region, and permits use of ZnO as pigment in ultraviolet-stable coatings based upon polymethyl siloxane elastomers and resins. Material has low absorptance/emittance ratio
Study of Bose-Einstein Correlations in e+e- -> W+W- events at LEP
Bose-Einstein correlation between like-sign charged-particle pairs in e+e- ->
W+W- events recorded with the OPAL detector at LEP at centre-of-mass energies
between 183 GeV and 209 GeV are studied. Recently proposed methods which allow
direct searches for correlations in the data via distributions of test
variables are used to investigate the presence of correlations between hadrons
originating from different W bosons in W+W- -> qqqq events. Within the
statistics of the data sample no evidence for inter-WW Bose-Einstein
correlations is obtained. The data are also compared with predictions of a
recent implementation of Bose-Einstein correlation effects in the Monte Carlo
model PYTHIA.Comment: 29 pages, 10 figures, Submitted to Eur. Phys. J.
Induced wormholes due to quantum effects of spherically reduced matter in large N approximation
Using one-loop effective action in large N and s-wave approximation we
discuss the possibility to induce primordial wormholes at the early Universe.
An analytical solution is found for self-consistent primordial wormhole with
constant radius. Numerical study gives the wormhole solution with increasing
throat radius and increasing red-shift function. There is also some indication
to the possibility of a topological phase transition.Comment: LaTeX file, 2 eps figures, 9 pages, few misprints are corrected,
numerics are change
Spectral energy distributions of quasars selected in the mid-infrared
We present preliminary results on fitting of SEDs to 142 z>1 quasars selected
in the mid-infrared. Our quasar selection finds objects ranging in extinction
from highly obscured, type-2 quasars, through more lightly reddened type-1
quasars and normal type-1s. We find a weak tendency for the objects with the
highest far-infrared emission to be obscured quasars, but no bulk systematic
offset between the far-infrared properties of dusty and normal quasars as might
be expected in the most naive evolutionary schemes. The hosts of the type-2
quasars have stellar masses comparable to those of radio galaxies at similar
redshifts. Many of the type-1s, and possibly one of the type-2s require a very
hot dust component in addition to the normal torus emission.Comment: 4 pages, 2 figures, to appear in the proceedings of The Spectral
Energy Distribution of Galaxies, Preston, September 2011, eds R.J. Tuffs &
C.C. Popesc
Space-time dependent couplings in N=1 SUSY gauge theories: Anomalies and Central Functions
We consider N=1 supersymmetric gauge theories in which the couplings are
allowed to be space-time dependent functions. Both the gauge and the
superpotential couplings become chiral superfields. As has recently been shown,
a new topological anomaly appears in models with space-time dependent gauge
coupling. Here we show how this anomaly may be used to derive the NSVZ beta
function in a particular, well-determined renormalisation scheme, both without
and with chiral matter. Moreover we extend the topological anomaly analysis to
theories coupled to a classical curved superspace background, and use it to
derive an all-order expression for the central charge c, the coefficient of the
Weyl tensor squared contribution to the conformal anomaly. We also comment on
the implications of our results for the central charge a expected to be of
relevance for a four-dimensional C-theorem.Comment: 28 pages, LaTeX, no figure
On metric geometry of conformal moduli spaces of four-dimensional superconformal theories
Conformal moduli spaces of four-dimensional superconformal theories obtained
by deformations of a superpotential are considered. These spaces possess a
natural metric (a Zamolodchikov metric). This metric is shown to be Kahler. The
proof is based on superconformal Ward identities.Comment: 8 page
Unified approach to study quantum properties of primordial black holes, wormholes and of quantum cosmology
We review the anomaly induced effective action for dilaton coupled spinors
and scalars in large N and s-wave approximation. It may be applied to study the
following fundamental problems: construction of quantum corrected black holes
(BHs), inducing of primordial wormholes in the early Universe (this effect is
confirmed) and the solution of initial singularity problem. The recently
discovered anti-evaporation of multiple horizon BHs is discussed. The existance
of such primordial BHs may be interpreted as SUSY manifestation. Quantum
corrections to BHs thermodynamics maybe also discussed within such scheme.Comment: LaTeX file and two eps files, to appear in MPLA, Brief Review
Constrained superpotentials in harmonic gauge theories with 8 supercharges
We consider D-dimensional supersymmetric gauge theories with 8 supercharges
(D<6,) in the framework of harmonic superspaces. The effective
Abelian low-energy action for D=5 contains the free and Chern-Simons terms.
Effective superfield actions for D<4 can be written in terms of
the superpotentials satisfying the superfield constraints and (6-D)-dimensional
Laplace equations. The role of alternative harmonic structures is discussed.Comment: LATEX file, 9 pages, version published in Teor. Mat. Fi
Infrared stability of ABJ-like theories
We consider marginal deformations of the superconformal ABJM/ABJ models which
preserve N=2 supersymmetry. We determine perturbatively the spectrum of fixed
points and study their infrared stability. We find a closed line of fixed
points which is IR stable. The fixed point corresponding to the ABJM/ABJ models
is stable under marginal deformations which respect the original SU(2)xSU(2)
invariance, while deformations which break this group destabilize the theory
which then flows to a less symmetric fixed point. We discuss the addition of
flavor degrees of freedom. We prove that in general a flavor marginal
superpotential does not destabilize the system in the IR. An exception is
represented by a marginal coupling which mixes matter charged under different
gauge sectors. Finally, we consider the case of relevant deformations which
should drive the system to a strongly coupled IR fixed point recently
investigated in arXiv:0909.2036 [hep-th].Comment: 1+11 pages, 4 figures; v2: minor correction
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