43 research outputs found
A QCD Sum Rule Approach to the Contribution to the Radiative Decay
QCD sum rules are used to calculate the contribution of short-distance
single-quark transition , to the amplitudes of the
hyperon radiative decay, . We re-evaluate the
Wilson coefficient of the effective operator responsible for this transition.
We obtain a branching ratio which is comparable to the unitarity limit.Comment: 15 pages, Revtex, 13 figures available as a uuencoded, gz-compressed
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Expanded Parameters in the Self-Organized Critical Forest Fire Model
The forest fire model has been used to test the theory of Self-Organized Criticality as a model of complexity. The goal is to search for scale invariance in randomly generated forest fires using a computer simulation. In a previous model by B. Drossel and F. Schwabl,1 power-law behavior was seen when the nearest neighbors to a tree on fire catch on fire, and it has been assumed that if further trees also catch fire, then it will still exhibit self-organized criticality, showing scale invariance. Testing this assumption aids to the exploration of the applicability of self-organized criticality because the model is the most useful when it applies to a large range of systems, as closely related to nature as possible.
1 B. Drossel and F. Schwabl, Phys. Rev. Lett. 69, 1629 (1992
Dilepton Spectra from Decays of Light Unflavored Mesons
The invariant mass spectrum of the and pairs
from decays of light unflavored mesons with masses below the -meson mass to final states containing along with a dilepton pair one
photon, one meson, and two mesons are calculated within the framework of the
effective meson theory. The results can be used for simulations of the dilepton
spectra in heavy-ion collisions and for experimental searches of dilepton meson
decays.Comment: 73 pages, 19 figures, 3 tables, REVTeX, new references adde
Synchronization of coupled limit cycles
A unified approach for analyzing synchronization in coupled systems of
autonomous differential equations is presented in this work. Through a careful
analysis of the variational equation of the coupled system we establish a
sufficient condition for synchronization in terms of the geometric properties
of the local limit cycles and the coupling operator. This result applies to a
large class of differential equation models in physics and biology. The
stability analysis is complemented with a discussion of numerical simulations
of a compartmental model of a neuron.Comment: Journal of Nonlinear Science, accepte
Astronomical Distance Determination in the Space Age: Secondary Distance Indicators
The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)
Increased vulnerability of postarthritic cartilage to a second arthritic insult: accelerated MMP activity in a flare up of arthritis
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