163,491 research outputs found
Limit theorems for Markov processes indexed by continuous time Galton--Watson trees
We study the evolution of a particle system whose genealogy is given by a
supercritical continuous time Galton--Watson tree. The particles move
independently according to a Markov process and when a branching event occurs,
the offspring locations depend on the position of the mother and the number of
offspring. We prove a law of large numbers for the empirical measure of
individuals alive at time t. This relies on a probabilistic interpretation of
its intensity by mean of an auxiliary process. The latter has the same
generator as the Markov process along the branches plus additional jumps,
associated with branching events of accelerated rate and biased distribution.
This comes from the fact that choosing an individual uniformly at time t favors
lineages with more branching events and larger offspring number. The central
limit theorem is considered on a special case. Several examples are developed,
including applications to splitting diffusions, cellular aging, branching
L\'{e}vy processes.Comment: Published in at http://dx.doi.org/10.1214/10-AAP757 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Weibull-type limiting distribution for replicative systems
The Weibull function is widely used to describe skew distributions observed
in nature. However, the origin of this ubiquity is not always obvious to
explain. In the present paper, we consider the well-known Galton-Watson
branching process describing simple replicative systems. The shape of the
resulting distribution, about which little has been known, is found essentially
indistinguishable from the Weibull form in a wide range of the branching
parameter; this can be seen from the exact series expansion for the cumulative
distribution, which takes a universal form. We also find that the branching
process can be mapped into a process of aggregation of clusters. In the
branching and aggregation process, the number of events considered for
branching and aggregation grows cumulatively in time, whereas, for the binomial
distribution, an independent event occurs at each time with a given success
probability.Comment: 6 pages and 5 figure
BES Results on Charmonium Decays and Transitions
Results are reported based on samples of 58 million and 14 million
decays obtained by the BESII experiment. Improved branching fraction
measurements are determined, including branching fractions for
, , , , anything , and
\psi(2S)\to\gamma\chi_{c1},\gamma\chi_{c2}\to\gamma\gamma\jpsi. Using 14
million events, production in decays
and production in decays are
observed for the first time, and branching ratios are determined.Comment: Parallel Talk presented at ICHEP04. 4 pages and 6 figure
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Asymmetric Time Evolution And Indistinguishable Events
With a time asymmetric theory, in which quantum mechanical time evolution is given by a semigroup of operators rather than by a group, the states of open systems are represented by density operators exhibiting a branching behavior. To treat the indistinguishably of the members of experimental ensembles, we hypothesize that environmental interference occurs during events that are themselves fundamentally indistinguishable.Center for Complex Quantum System
Dynamical scaling in branching models for seismicity
We propose a branching process based on a dynamical scaling hypothesis
relating time and mass. In the context of earthquake occurrence, we show that
experimental power laws in size and time distribution naturally originate
solely from this scaling hypothesis. We present a numerical protocol able to
generate a synthetic catalog with an arbitrary large number of events. The
numerical data reproduce the hierarchical organization in time and magnitude of
experimental inter-event time distribution.Comment: 3 figures to appear on Physical Review Letter
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