46,277 research outputs found
Isoscaling as a measure of Symmetry Energy in the Lattice Gas Model
The energetic properties of nuclear clusters inside a low-density,
finite-temperature medium are studied with a Lattice Gas Model including
isospin dependence and Coulomb forces. Important deviations are observed
respect to the Fisher approximation of an ideal gas of non-interacting
clusters, but the global energetics can still be approximately expressed in
terms of a simple modified energy-density functional. The multi-fragmentation
regime appears dominated by combinatorial effects in this model, but the
isoscaling of the largest fragment in low energy collisions appears a promising
observable for the experimental measurement of the symmetry energy.Comment: 4 pages, 3 figure, submitted to PR
SUSY signals at HERA in the no-scale flipped SU(5) supergravity model
Sparticle production and detection at HERA are studied within the recently
proposed no-scale flipped supergravity model. Among the various
reaction channels that could lead to sparticle production at HERA, only the
following are within its limit of sensitivity in this model: , where are the
two lightest neutralinos and is the lightest chargino. We study the
elastic and deep-inelastic contributions to the cross sections using the
Weizs\"acker-Williams approximation. We find that the most promising
supersymmetric production channel is right-handed selectron ()
plus first neutralino (), with one hard electron and missing energy
signature. The channel leads to comparable rates but also
allows jet final states. A right-handedly polarized electron beam at HERA would
shut off the latter channel and allow preferentially the former one. With an
integrated luminosity of {\cal L}=100\ipb, HERA can extend the present LEPI
lower bounds on by
\approx25\GeV, while {\cal L}=1000\ipb will make HERA competitive with
LEPII. We also show that the Leading Proton Spectrometer (LPS) at HERA is an
excellent supersymmetry detector which can provide indirect information about
the sparticle masses by measuring the leading proton longitudinal momentum
distribution.Comment: 11 pages, 8 figures (available upon request as uuencoded file or
separate ps files), tex (harvmac) CTP-TAMU-15/93, CERN/LAA/93-1
HeteroGenius: A Framework for Hybrid Analysis of Heterogeneous Software Specifications
Nowadays, software artifacts are ubiquitous in our lives being an essential
part of home appliances, cars, cell phones, and even in more critical
activities like aeronautics and health sciences. In this context software
failures may produce enormous losses, either economical or, in the worst case,
in human lives. Software analysis is an area in software engineering concerned
with the application of diverse techniques in order to prove the absence of
errors in software pieces. In many cases different analysis techniques are
applied by following specific methodological combinations that ensure better
results. These interactions between tools are usually carried out at the user
level and it is not supported by the tools. In this work we present
HeteroGenius, a framework conceived to develop tools that allow users to
perform hybrid analysis of heterogeneous software specifications.
HeteroGenius was designed prioritising the possibility of adding new
specification languages and analysis tools and enabling a synergic relation of
the techniques under a graphical interface satisfying several well-known
usability enhancement criteria. As a case-study we implemented the
functionality of Dynamite on top of HeteroGenius.Comment: In Proceedings LAFM 2013, arXiv:1401.056
Singling out the effect of quenched disorder in the phase diagram of cuprates
We investigate the specific influence of structural disorder on the
suppression of antiferromagnetic order and on the emergence of cuprate
superconductivity. We single out pure disorder, by focusing on a series of
YEuBaCuO samples at fixed oxygen content
, in the range . The gradual Y/Eu isovalent substitution
smoothly drives the system through the Mott-insulator to superconductor
transition from a full antiferromagnet with N\'eel transition K at
to a bulk superconductor with superconducting critical temperature
K at , YBaCuO. The electronic properties are
finely tuned by gradual lattice deformations induced by the different cationic
radii of the two lanthanides, inducing a continuous change of the basal Cu(1)-O
chain length, as well as a controlled amount of disorder in the active
Cu(2)O bilayers. We check that internal charge transfer from the basal to
the active plane is entirely responsible for the doping of the latter and we
show that superconductivity emerges with orthorhombicity. By comparing
transition temperatures with those of the isoelectronic clean system we
deterime the influence of pure structural disorder connected with the Y/Eu
alloy.Comment: 10 pages 11 figures, submitted to Journal of Physics: Condensed
Matter, Special Issue in memory of Prof. Sandro Massid
Combined frequency-amplitude nonlinear modulation: theory and applications
In this work we formulate a generalized theoretical model to describe the
nonlinear dynamics observed in combined frequency-amplitude modulators whose
characteristic parameters exhibit a nonlinear dependence on the input
modulating signal. The derived analytical solution may give a satisfactory
explanation of recent laboratory observations on magnetic spin-transfer
oscillators and fully agrees with results of micromagnetic calculations. Since
the theory has been developed independently of the mechanism causing the
nonlinearities, it may encompass the description of modulation processes of any
physical nature, a promising feature for potential applications in the field of
communication systems.Comment: 8 pages, 4 figures, to be published on IEEE Transactions on Magnetic
Phenomenology Tools on Cloud Infrastructures using OpenStack
We present a new environment for computations in particle physics
phenomenology employing recent developments in cloud computing. On this
environment users can create and manage "virtual" machines on which the
phenomenology codes/tools can be deployed easily in an automated way. We
analyze the performance of this environment based on "virtual" machines versus
the utilization of "real" physical hardware. In this way we provide a
qualitative result for the influence of the host operating system on the
performance of a representative set of applications for phenomenology
calculations.Comment: 25 pages, 12 figures; information on memory usage included, as well
as minor modifications. Version to appear in EPJ
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