14,322 research outputs found
The Local Structure of Lie Bialgebroids
We study the local structure of Lie bialgebroids at regular points. In
particular, we classify all transitive Lie bialgebroids. In special cases, they
are connected to classical dynamical -matrices and matched pairs induced by
Poisson group actionsComment: 13 page
Star formation associated with a large-scale infrared bubble
Using the data from the Galactic Ring Survey (GRS) and Galactic Legacy
Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), we performed a study for a
large-scale infrared bubble with a size of about 16 pc at a distance of 2.0
kpc. We present the 12CO J=1-0, 13CO J=1-0 and C18O J=1-0 observations of HII
region G53.54-0.01 (Sh2-82) obtained at the the Purple Mountain Observation
(PMO) 13.7 m radio telescope to investigate the detailed distribution of
associated molecular material. The large-scale infrared bubble shows a
half-shell morphology at 8 um. H II regions G53.54-0.01, G53.64+0.24, and
G54.09-0.06 are situated on the bubble. Comparing the radio recombination line
velocities and associated 13CO J=1-0 components of the three H II regions, we
found that the 8 um emission associated with H II region G53.54-0.01 should
belong to the foreground emission, and only overlap with the large-scale
infrared bubble in the line of sight. Three extended green objects (EGOs, the
candidate massive young stellar objects), as well as three H II regions and two
small-scale bubbles are found located in the G54.09-0.06 complex, indicating an
active massive star-forming region. C18O J=1-0 emission presents four cloud
clumps on the northeastern border of H II region G53.54-0.01. Via comparing the
spectral profiles of 12CO J=1-0, 13CO J=1-0, and C18O J=1-0 peak at each clump,
we found the collected gas in the three clumps, except for the clump coincided
with a massive YSO (IRAS 19282+1814). Using the evolutive model of H II region,
we derived that the age of H II region G53.54-0.01 is 1.5*10^6 yr. The
significant enhancement of several Class I and Class II YSOs around G53.54-0.01
indicates the presence of some recently formed stars, which may be triggered by
this H II region through the collect and collapse (CC) process.Comment: 9 pages, 6 figures, accepted for publication in A&
Manin Triples for Lie Bialgebroids
In his study of Dirac structures, a notion which includes both Poisson
structures and closed 2-forms, T. Courant introduced a bracket on the direct
sum of vector fields and 1-forms. This bracket does not satisfy the Jacobi
identity except on certain subspaces. In this paper we systematize the
properties of this bracket in the definition of a Courant algebroid. This
structure on a vector bundle , consists of an antisymmetric
bracket on the sections of whose ``Jacobi anomaly'' has an explicit
expression in terms of a bundle map and a field of symmetric
bilinear forms on . When is a point, the definition reduces to that of a
Lie algebra carrying an invariant nondegenerate symmetric bilinear form.
For any Lie bialgebroid over (a notion defined by Mackenzie
and Xu), there is a natural Courant algebroid structure on
which is the Drinfel'd double of a Lie bialgebra when is a point.
Conversely, if and are complementary isotropic subbundles of a
Courant algebroid , closed under the bracket (such a bundle, with dimension
half that of , is called a Dirac structure), there is a natural Lie
bialgebroid structure on whose double is isomorphic to . The
theory of Manin triples is thereby extended from Lie algebras to Lie
algebroids.
Our work gives a new approach to bihamiltonian structures and a new way of
combining two Poisson structures to obtain a third one. We also take some
tentative steps toward generalizing Drinfel'd's theory of Poisson homogeneous
spaces from groups to groupoids.Comment: 24 pages, LaTeX2e (minor corrections, added section at end), final
version of paper to appear in J. Diff. Geo
Implication the observed for studying the process
We study the charmonium reaction using
effective lagrangian approach where the contributions from well established
states are considered, and all parameters are fixed in the process of
at center of mass energy GeV.
The experimental data on the line shape of the mass distribution of the can be well reproduced. Based on the studying of , the total and differential cross sections of the reaction are predicted. At the same time we evaluated
also the cross sections of the reaction. It is
shown that the contribution of nucleon pole to this reaction is largest close
to the reaction threshold. However, the interference between nucleon pole and
the other nucleon resonance can still change the angle distributions
significantly. Those theoretical results may be test by the future experiments
at \overline{\mbox{P}}ANDA.Comment: 8 pages, 10 figures, and 4 tables. More discussions added and typos
corrected. Accepted by Eur. Phys. J.
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