343 research outputs found
New Solutions to the Firing Squad Synchronization Problems for Neural and Hyperdag P Systems
We propose two uniform solutions to an open question: the Firing Squad
Synchronization Problem (FSSP), for hyperdag and symmetric neural P systems,
with anonymous cells. Our solutions take e_c+5 and 6e_c+7 steps, respectively,
where e_c is the eccentricity of the commander cell of the dag or digraph
underlying these P systems. The first and fast solution is based on a novel
proposal, which dynamically extends P systems with mobile channels. The second
solution is substantially longer, but is solely based on classical rules and
static channels. In contrast to the previous solutions, which work for
tree-based P systems, our solutions synchronize to any subset of the underlying
digraph; and do not require membrane polarizations or conditional rules, but
require states, as typically used in hyperdag and neural P systems
The recent sovereign debt crisis in the Euro zone: A matter of fundamentals?
The idea that the Euro zone sovereign debt crisis was caused by structural weaknesses degenerating into fundamental macroeconomic imbalances in the peripheral countries prevails among international institutions such as the IMF, the ECB, and the European Commission. On the contrary, some economists believe that this crisis is the consequence of major deficiencies in the architecture of economic policy making in the Euro zone that did not allow a proper response to a global systemic crisis of the financial markets that started in the United States. The objective of this paper is to provide a better understanding of the public debt dynamics in the EU, differentiating the case of Euro zone peripheral countries. We used quarterly data from 2000 to 2011 to estimate a small-scale model that takes into account the interactions between key variables. Our results do not support entirely the official view. We conclude that the cause of the adverse debt dynamics unravelling after 2007 was a sharp GDP contraction, coupled with a substantial increase in the interest cost of debt finance due to higher self-fulfilling solvency risks perceived by creditors, interacting with a higher sensitiveness of Euro zone peripheral countries to fundamentals
Quark coalescence in the mid rapidity region at RHIC
We utilize the ALCOR model for mid-rapidity hadron number predictions at AGS,
SPS and RHIC energies. We present simple fits for the energy dependence of
stopping and quark production.Comment: Talk given at SQM2001, Frankfurt, (LaTeX 8 pages, 5 .ps figs
Heisenberg's Universal (lns)**2 Increase of Total Cross Sections
The (lns)**2 behaviour of total cross-sections, first obtained by Heisenberg
50 years ago, receives now increased interest both on phenomenological and
theoretical levels. In this paper we present a modification of the Heisenberg's
model in connection with the presence of glueballs and we show that it leads to
a realistic description of all existing hadron total cross-section data.Comment: 6 pages, 3 figure
Possible Interpretations of If It Really Exists
We analyze various possible interpretations of the narrow state
observed by SELEX Collaboration recently, which lies above
threshold and has abnormal decay pattern. These interpretations include: (1)
several versions of tetraquarks; (2) conventional meson such as the
first radial excitation of with abnormally large SU(3) symmetry
breaking; (3) conventional meson with abnormally large
coupling; (4) heavy hybrid meson. We discuss the physical implications of each
interpretation. For example, if the existence of is confirmed
as the first radial excitation of by other experiments, it will be
helpful to look for (1) its SU(3) flavor partners ; (2) its
B-meson analogues ; (3) S-wave two pion
decay modes
Benchmarks for the Forward Observables at RHIC, the Tevatron-run II and the LHC
We present predictions on the total cross sections and on the ratio of the
real part to the imaginary part of the elastic amplitude (rho parameter) for
present and future pp and pbar p colliders, and on total cross sections for
gamma p -> hadrons at cosmic-ray energies and for gamma gamma-> hadrons up to
sqrt{s}=1 TeV. These predictions are based on an extensive study of possible
analytic parametrisations invoking the biggest hadronic dataset available at
t=0. The uncertainties on total cross sections, including the systematic errors
due to contradictory data points from FNAL, can reach 1.9% at RHIC, 3.1% at the
Tevatron, and 4.8% at the LHC, whereas those on the rho parameter are
respectively 5.4%, 5.2%, and 5.4%.Comment: 11 pages, 2 figures, 4 tables, RevTeX
Spin asymmetries for elastic proton scattering and the spin dependent couplings of the Pomeron
This paper serves as a report on the large amount of analysis done in
conjunction with the polarized proton program at RHIC. This comprises elastic
scattering data of protons on protons in colliding beam or fixed target mode
and proton beams on carbon targets. In addition to providing a model for the
energy dependence of the analyzing power of elastic scattering needed for
proton polarimetry, it also provides some significant information about the
spin dependence of dominant Regge poles. Most notably, the data indicates that
the Pomeron has a significant spin-flip coupling. This allows the exploration
of the double spin flip asymmetry A_{NN} for which some data over a wide energy
range is now available, along with a concrete realization of a proposed Odderon
search.Comment: final reference modife
P-P Total Cross Sections at VHE from Accelerator Data
Comparison of P-P total cross-sections estimations at very high energies -
from accelerators and cosmic rays - shows a disagreement amounting to more than
10 %, a discrepancy which is beyond statistical errors. Here we use a
phenomenological model based on the Multiple-Diffraction approach to
successfully describe data at accelerator energies. The predictions of the
model are compared with data On the basis of regression analysis we determine
confident error bands, analyzing the sensitivity of our predictions to the
employed data for extrapolation. : using data at 546 and 1.8 TeV, our
extrapolations for p-p total cross-sections are only compatible with the Akeno
cosmic ray data, predicting a slower rise with energy than other cosmic ray
results and other extrapolation methods. We discuss our results within the
context of constraints in the light of future accelerator and cosmic ray
experimental results.Comment: 26 pages aqnd 11 figure
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