965 research outputs found
Experimental local realism tests without fair sampling assumption
Following the theoretical suggestion of Ref. [1,2], we present experimental
results addressed to test restricted families of local realistic models, but
without relying on the fair sampling assumption
Determination of MSSM Parameters from LHC and ILC Observables in a Global Fit
We present the results of a realistic global fit of the Lagrangian parameters
of the Minimal Supersymmetric Standard Model assuming universality for the
first and second generation and real parameters. No assumptions on the SUSY
breaking mechanism are made. The fit is performed using the precision of future
mass measurements of superpartners at the LHC and mass and polarized
topological cross-section measurements at the ILC. Higher order radiative
corrections are accounted for whereever possible to date. Results are obtained
for a modified SPS1a MSSM benchmark scenario but they were checked not to
depend critically on this assumption. Exploiting a simulated annealing
algorithm, a stable result is obtained without any a priori assumptions on the
values of the fit parameters. Most of the Lagrangian parameters can be
extracted at the percent level or better if theoretical uncertainties are
neglected. Neither LHC nor ILC measurements alone will be sufficient to obtain
a stable result. The effects of theoretical uncertainties arising from unknown
higher-order corrections and parametric uncertainties are examined
qualitatively. They appear to be relevant and the result motivates further
precision calculations. The obtained parameters at the electroweak scale are
used for a fit of the parameters at high energy scales within the bottom-up
approach. In this way regularities at these scales are explored and the
underlying model can be determined with hardly any theoretical bias. Fits of
high-scale parameters to combined LHC+ILC measurements within the mSUGRA
framework reveal that even tiny distortions in the low-energy mass spectrum
already lead to inacceptable chi^2 values. This does not hold for ``LHC only''
inputs.Comment: 25 pages, 5 figure
Antihyperon-Production in Relativistic Heavy Ion Collision
Recently it has been shown that the observed antiproton yield in heavy-ion
collisions at CERN-SpS energies can be understood by multi-pionic interactions
which enforce local chemical equilibrium of the antiprotons with the nucleons
and pions. Here we show that antihyperons are driven towards local chemical
equilibrium with pions, nucleons and kaons on a timescale of less than 3 fm/c
when applying a similar argument for the antihyperons by considering the
inverse channel of annihilation reactions anti-Y + p to pions + kaons. These
multi-mesonic reactions easily explain the antihyperon yields at CERN-SpS
energies as advertised in pure thermal, hadronic models without the need of a
quark gluon plasma phase. In addition, the argument also applies for AGS
energies.Comment: 4 pages using RevTeX, 1 eps figur
Josephson oscillation of a superfluid Fermi gas
Using the complete numerical solution of a time-dependent three-dimensional
mean-field model we study the Josephson oscillation of a superfluid Fermi gas
(SFG) at zero temperature formed in a combined axially-symmetric harmonic plus
one-dimensional periodic optical-lattice (OL) potentials after displacing the
harmonic trap along the axial OL axis. We study the dependence of Josephson
frequency on the strength of the OL potential. The Josephson frequency
decreases with increasing strength as found in the experiment of Cataliotti et
al. [Science 293 (2001) 843] for a Bose-Einstein condensate and of the
experiment of Pezze et al. [Phys. Rev. Lett. 93 (2004) 120401] for an ideal
Fermi gas. We demonstrate a breakdown of Josephson oscillation in the SFG for a
large displacement of the harmonic trap. These features of Josephson
oscillation of a SFG can be tested experimentally.Comment: 7 pages, 10 figure
Transport of a quantum degenerate heteronuclear Bose-Fermi mixture in a harmonic trap
We report on the transport of mixed quantum degenerate gases of bosonic 87Rb
and fermionic 40K in a harmonic potential provided by a modified QUIC trap. The
samples are transported over a distance of 6 mm to the geometric center of the
anti-Helmholtz coils of the QUIC trap. This transport mechanism was implemented
by a small modification of the QUIC trap and is free of losses and heating. It
allows all experiments using QUIC traps to use the highly homogeneous magnetic
fields that can be created in the center of a QUIC trap and improves the
optical access to the atoms, e.g., for experiments with optical lattices. This
mechanism may be cascaded to cover even larger distances for applications with
quantum degenerate samples.Comment: 7 pages, 8 figure
Euclidean versus hyperbolic congestion in idealized versus experimental networks
This paper proposes a mathematical justification of the phenomenon of extreme
congestion at a very limited number of nodes in very large networks. It is
argued that this phenomenon occurs as a combination of the negative curvature
property of the network together with minimum length routing. More
specifically, it is shown that, in a large n-dimensional hyperbolic ball B of
radius R viewed as a roughly similar model of a Gromov hyperbolic network, the
proportion of traffic paths transiting through a small ball near the center is
independent of the radius R whereas, in a Euclidean ball, the same proportion
scales as 1/R^{n-1}. This discrepancy persists for the traffic load, which at
the center of the hyperbolic ball scales as the square of the volume, whereas
the same traffic load scales as the volume to the power (n+1)/n in the
Euclidean ball. This provides a theoretical justification of the experimental
exponent discrepancy observed by Narayan and Saniee between traffic loads in
Gromov-hyperbolic networks from the Rocketfuel data base and synthetic
Euclidean lattice networks. It is further conjectured that for networks that do
not enjoy the obvious symmetry of hyperbolic and Euclidean balls, the point of
maximum traffic is near the center of mass of the network.Comment: 23 pages, 4 figure
Analysis of the Neutralino System in Three--Body Leptonic Decays of Neutralinos
Neutralinos in supersymmetric theories, the spin--1/2
Majorana--type superpartners of the U(1) and SU(2) neutral electroweak gauge
bosons and SU(2) neutral Higgs bosons, are expected to be among light
supersymmetric particles so that they can be produced copiouslyvia direct pair
production and/or from cascade decays of other sparticles such as sleptons at
the planned Large Hadron Collider and the prospective International Linear
Collider. Considering the prospects of having both highly polarized neutralinos
and possibility of reconstructing their decay rest frames, we provide a
systematic investigation of the three--body leptonic decays of the neutralinos
in the minimal supersymmetric standard model and demonstrate alternative ways
for probing the Majorana nature of the neutralinos and CP violation in the
neutralino system.Comment: Version to appear in Eur.Phys.J.
Understanding edge-connectivity in the Internet through core-decomposition
Internet is a complex network composed by several networks: the Autonomous
Systems, each one designed to transport information efficiently. Routing
protocols aim to find paths between nodes whenever it is possible (i.e., the
network is not partitioned), or to find paths verifying specific constraints
(e.g., a certain QoS is required). As connectivity is a measure related to both
of them (partitions and selected paths) this work provides a formal lower bound
to it based on core-decomposition, under certain conditions, and low complexity
algorithms to find it. We apply them to analyze maps obtained from the
prominent Internet mapping projects, using the LaNet-vi open-source software
for its visualization
Production of a microbeam of slow highly charged ions with a tapered glass capillary
journal articl
Contribution of Compton Scattering in Problems Associated with Measuring the Surface Density of Radiation Protection Coatings
The paper analyses the ratio between the number of Compton-scattered quanta excited in elements of radiation protection coatings by isotope Am-241 and the number of fluorescence quanta excited in in the same elements, taking into account the fluorescence yield coefficient and the distance between the energy of primary radiation quanta (60 keV) and the energy of absorption K-edge. The paper shows that the number of scattered quanta exceeds the number of fluorescent quanta from K-level in all elements. The obtained values define the ratio of scattered and fluorescent quanta in any radiation protection coatings with a known chemical composition
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