2,149 research outputs found
Coil-to-globule transition by dissipative particle dynamics simulation
The dynamics of a collapsing polymer under a temperature quench in dilute solution is investigated by dissipative particles dynamics. Hydrodynamic interactions and many-body interaction are preserved naturally by incorporating explicit solvent particles in this approach. Our simulation suggests a four-stage collapse pathway: localized clusters formation, cluster coarsening in situ, coarsening involving global backbone conformation change into a crumpled globule, and compaction of the globule. For all the quench depths and chain lengths used in our study, collapse proceeds without the chain getting trapped in a metastable βsausageβ configuration, as reported in some earlier studies. We obtain the time scales for each of the first three stages, as well as its scaling with the quench depths ΞΎ and chain lengths N. The total collapse time scales as Ο_c ~ ΞΎ^(β0.46 Β± 0.04)N^(0.98 Β± 0.09), with the quench depth and degree of polymerization
The analysis of the charmonium-like states ,, , and according to its strong decay behaviors
Inspired by the newly observed state , we analyze the strong
decay behaviors of some charmonium-like states ,,
, and by the model. We carry out our
work based on the hypothesis that these states are all being the charmonium
systems. Our analysis indicates that charmonium state can be a good
candidate for and state is the possible assignment for
. Considering as the state, the decay behavior of
is inconsistent with the experimental data. So, we can not assign
as the charmonium state by present work. Besides, our
analysis imply that it is reasonable to assign and to be
the same state, . However, combining our analysis with that of
Zhou~\cite{ZhouZY}, we speculate that / might not be a pure
systems
Strong coupling constants and radiative decays of the heavy tensor mesons
In this article, we analyze tensor-vector-pseudoscalar(TVP) type of vertices
, , ,
, , ,
, , and
, in the frame work of three point QCD sum rules.
According to these analysis, we calculate their strong form factors which are
used to fit into analytical functions of . Then, we obtain the strong
coupling constants by extrapolating these strong form factors into deep
time-like regions. As an application of this work, the coupling constants for
radiative decays of these heavy tensor mesons are also calculated at the point
of . With these coupling constants, we finally calculate the radiative
decay widths of these tensor mesons.Comment: arXiv admin note: text overlap with arXiv:1810.0597
Analysis of the strong coupling form factors of and in QCD sum rules
In this article, we study the strong interaction of the vertexes
and using the three-point QCD sum rules under two different dirac
structures. Considering the contributions of the vacuum condensates up to
dimension in the operation product expansion, the form factors of these
vertexes are calculated. Then, we fit the form factors into analytical
functions and extrapolate them into time-like regions, which giving the
coupling constant. Our analysis indicates that the coupling constant for these
two vertexes are and
.Comment: 6 figure
Analysis of the charmed mesons , and
In this work, we systematically study the strong decay behaviors of the
charmed mesons , and
reported by the LHCb collaboration. By comparing the masses and the decay
properties with the results of the experiment, we assigned these newly observed
mesons as the , and
states respectively. As a byproduct, we also study the
strong decays of the unobserved and
charmed mesons, which is helpful to the future experiments in searching for
these charmed mesons.Comment: arXiv admin note: text overlap with arXiv:0803.0106 by other author
Systematic analysis of the , , , , and in meson family
In this work, we tentatively assign the charmed mesons ,
, , , and
observed by the LHCb collaboration according to their
spin-parity and masses, then study their strong decays to the ground state
charmed mesons plus light pseudoscalar mesons with the model.
According to these study, we assigned the as the
state, the as the
or state, the as the or
state in the meson family. As a byproduct, we also
study the strong decays of ,,
, etc, states, which will be helpful
to further experimentally study mixings of these mesons.Comment: 16 pages,1 figure. arXiv admin note: text overlap with
arXiv:0801.4821 by other author
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