527 research outputs found
On Khintchine exponents and Lyapunov exponents of continued fractions
Assume that admits its continued fraction expansion . The Khintchine exponent of is defined by
when
the limit exists. Khintchine spectrum is fully studied, where and denotes the
Hausdorff dimension. In particular, we prove the remarkable fact that the
Khintchine spectrum , as function of , is
neither concave nor convex. This is a new phenomenon from the usual point of
view of multifractal analysis. Fast Khintchine exponents defined by
are also studied, where tends to the infinity faster than
does. Under some regular conditions on , it is proved that the fast
Khintchine spectrum is a
constant function. Our method also works for other spectra like the Lyapunov
spectrum and the fast Lyapunov spectrum.Comment: 37 pages, 5 figures, accepted by Ergodic Theory and Dyanmical System
Practice on the Watershed Hydrological Experimental System Reconciling Deterministic and Stochastic Subjects Based on the System Complexity: 1. Theoretical Study
This is the first of a two-part series on the watershed hydrological experimental system (WHES). Since the foundational stage and developmental stage of hydrological basin study with a duration of more than ca. one century, facing with the changing environment and, the declined risk of field study while the catchment hydrology is trapped in a theoretical impasse, a third phase of renovation on hydrological experiments seems ready to come out inevitably. Learned from Chinese decades’ experiences on the field basin study for the question of what is wrong with the status quo, our exploratory idea is reported in this part. From the viewpoint of general system theory based on the paralleled concepts of the ancient Chinese and the Western, it is considered that the adequate method should face the characters of the complex dynamic system instead of previous static, linear system. From the viewpoint of another philosophical paralleled concept of the Middle Way, it should also face the operation and organizing of the mesoscopic systems for the organized complexity. Then, a framework of WHES is suggested with its organization based on the strategy of constrain complexity and add complexity and on the strategy of manipulation including the artificial-natural and controlled-natural objects. Such a trial framework, the Chuzhou WHES, is reported including the suggested critical zone experimental block (CZEB) instead of the experimental basin (EB) in the last decades
Practices on the Watershed Hydrological Experimental System Reconciling Deterministic and Stochastic Subjects Based on the System Complexity: 2. Practice and Test
This is the second of a two-part series on the watershed hydrological experimental system (WHES) aimed at practice and test of it at Chuzhou Hydrology Laboratory. It constitutes both natural and artificial entities of different scales, within which two typical main subjects are reviewed here. First is a natural watershed Nandadish, which is subjected to be a Critical Zone Experimental Block, under manipulation strategy of constrain complexity to compare with the pure natural watersheds, it is the controlled-natural as we termed. Second is an artificial catchment Hydrohill, under the strategy of add complexity to compare with the simple artificial lysimeters, it is the artificial-natural as we termed. The constructions and instrumentations of these experimental catchments are reviewed, especially their renovation version during recent years after a long abandonment. Some results get during the operation of Chuzhou WHES are outlined here as well
Study of and and
We study the decays of and to the final states
and based on a single
baryon tag method using data samples of
and events collected with
the BESIII detector at the BEPCII collider. The decays to
are observed for the first time. The
measured branching fractions of and
are in good agreement with, and much
more precise, than the previously published results. The angular parameters for
these decays are also measured for the first time. The measured angular decay
parameter for , , is found to be negative, different to the other
decay processes in this measurement. In addition, the "12\% rule" and isospin
symmetry in the and and
systems are tested.Comment: 11 pages, 7 figures. This version is consistent with paper published
in Phys.Lett. B770 (2017) 217-22
Measurement of the proton form factor by studying
Using data samples collected with the BESIII detector at the BEPCII collider,
we measure the Born cross section of at 12
center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective
electromagnetic form factor of the proton is deduced under the assumption that
the electric and magnetic form factors are equal . In
addition, the ratio of electric to magnetic form factors, , and
are extracted by fitting the polar angle distribution of the proton
for the data samples with larger statistics, namely at 2232.4 and
2400.0 MeV and a combined sample at = 3050.0, 3060.0 and 3080.0 MeV,
respectively. The measured cross sections are in agreement with recent results
from BaBar, improving the overall uncertainty by about 30\%. The
ratios are close to unity and consistent with BaBar results in
the same region, which indicates the data are consistent with the
assumption that within uncertainties.Comment: 13 pages, 24 figure
Observation of the state in at BESIII
We report the observation of the in the process with a statistical
significance of , in data samples at center-of-mass energies
4.230, 4.260, 4.360, 4.420 and 4.600~GeV collected with the BESIII
detector at the BEPCII electron positron collider. The measured mass of the
is ~MeV/, where the first error is
statistical and the second systematic, and the width is less than ~MeV at
the 90\% confidence level. The products of the Born cross sections for
and the branching ratio are also measured. These measurements are in good
agreement with the assignment of the as the charmonium
state.Comment: 7 pages, 3 figures, version to appear in Phys. Rev. Let
Precision measurement of the decay branching fractions
Using 482 pb of data taken at GeV, we measure the
branching fractions of the decays of into and
to be \BR(D^{*0} \to D^0\pi^0)=(65.5\pm 0.8\pm 0.5)% and \BR(D^{*0} \to
D^0\gamma)=(34.5\pm 0.8\pm 0.5)% respectively, by assuming that the
decays only into these two modes. The ratio of the two branching fractions is
\BR(D^{*0} \to D^0\pi^0)/\BR(D^{*0} \to D^0\gamma) =1.90\pm 0.07\pm 0.05,
which is independent of the assumption made above. The first uncertainties are
statistical and the second ones systematic. The precision is improved by a
factor of three compared to the present world average values
Observation of the Dalitz Decay
We report the first observation of the Dalitz decay , based on a data sample of 1.31 billion events collected with
the BESIII detector. The mesons are produced via the decay process. The ratio is measured to be
. This
corresponds to a branching fraction . The transition form
factor is extracted and different expressions are compared to the measured
dependence on the invariant mass. The results are consistent with the
prediction of the Vector Meson Dominance model.Comment: 11 pages,7 figure
Improved measurement of the absolute branching fraction of
By analyzing 2.93 fb of data collected at GeV with the
BESIII detector, we measure the absolute branching fraction , which is consistent with previous measurements within
uncertainties but with significantly improved precision. Combining the Particle
Data Group values of , , and the lifetimes of the and
mesons with the value of measured in this work, we determine the following ratios of
partial widths: and .Comment: 9 pages; 8 figure
Determination of the number of events with inclusive decays
A measurement of the number of events collected with the BESIII
detector in 2009 and 2012 is performed using inclusive decays of the .
The number of events taken in 2009 is recalculated to be
, which is in good agreement with the previous
measurement, but with significantly improved precision due to improvements in
the BESIII software. The number of events taken in 2012 is determined
to be . In total, the number of events
collected with the BESIII detector is measured to be , where the uncertainty is dominated by systematic effects and the
statistical uncertainty is negligible.Comment: 10 pages, 6 figure
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