5,262 research outputs found
as a molecule from the pole counting rule
A comprehensive study on the nature of the resonant structure is
carried out in this work. By constructing the pertinent effective Lagrangians
and considering the important final-state-interaction effects, we first give a
unified description to all the relevant experimental data available, including
the and invariant mass distributions from the process, the distribution from and
also the spectrum in the process.
After fitting the unknown parameters to the previous data, we search the pole
in the complex energy plane and find only one pole in the nearby energy region
in different Riemann sheets. Therefore we conclude that is of
molecular nature, according to the pole counting rule
method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We
emphasize that the conclusion based upon the pole counting method is not
trivial, since both the contact interactions and the explicit
exchanges are introduced in our analyses and they lead to the same
conclusion.Comment: 21 pages, 9 figures. To match the published version in PRD.
Additional discussion on the spectral density function is include
X(3872) and its production at hadron colliders
We evaluate the production cross sections of at the LHC and
Tevatron at NLO in in NRQCD by assuming that the short-distance
production proceeds dominantly through its component in our
\chi_{c1}'\mbox{-}D^0\bar{D}^{*0} mixing model for . The outcomes of
the fits to the CMS distribution can well account for the recent ATLAS
data in a much larger range of transverse momenta
(10~\mbox{GeV}), and the CDF total cross section data, and
are also consistent with the value of constrained by the -meson decay data. %It can also well
describe the behavior of the CDF data, which show a strong
%resemblance to that of the X(3872). For LHCb the predicted X(3872) total cross
section is larger than the data by a factor of 2, which is due to the problem
of the fixed-order NRQCD calculation that may not be applicable for the region
with small (p_T\sim 5 ~\mbox{GeV}) and large forward rapidity
. In comparison, the prediction of molecule production mechanism
for is inconsistent with both distributions and total cross
sections of CMS and ATLAS, and the total cross section of CDF.Comment: Version published in PRD. More explanations added for the LHCb data.
More references added for recent experimental and theoretical results: the
ATLAS measurement on the X(3872) pT distribution in 10-70 GeV; the LHCb
measurement on the X(3872) radiative decays; the lattice calculation on
X(3872); the small resummation method, etc. No changes for the calculated
result and the conclusio
Some remarks on compositeness of
Recently LHCb experimental group find an exotic state from the
process . A key question is if it is just a
molecule or may have confined tetraquark ingredient. To investigate this,
different methods are taken, including two channel ( and
) K-matrix unitarization and single channel Flatt\'e-like
parametrization method analysed by pole counting rule and spectral density
function sum rule. It demonstrates that is a molecular state, though
the possibility that there may exist elementary ingredient can not be excluded,
by rough analysis on its production rate
A modified VMAT adaptive radiotherapy for nasopharyngeal cancer patients based on CT-CT image fusion
On the nature of X(3960)
A near-threshold enhancement in the system, dubbed as
, is observed by the LHCb collaboration recently. A combined analysis
on , , and
is performed using both a -matrix approach of
four-point contact interactions and a model of
Flatt\'e-like parameterizations. The use of the pole counting rule and spectral
density function sum rule %provides consistent evidence indicate, under current
statistics, that this near-threshold state has probably the mixed
nature of a confining state and continuum.Comment: 8 pages, 4 figures, 5 table
Anomalous Thermal Transport of SrTiO Driven by Anharmonic Phonon Renormalization
SrTiO has been extensively investigated owing to its abundant degrees of
freedom for modulation. However, the microscopic mechanism of thermal transport
especially the relationship between phonon scattering and lattice distortion
during the phase transition are missing and unclear. Based on deep-potential
molecular dynamics and self-consistent \textit{ab initio} lattice dynamics, we
explore the lattice anharmonicity-induced tetragonal-to-cubic phase transition
and explain this anomalous behavior during the phase transition. Our results
indicate the significant role of the renormalization of third-order interatomic
force constants to second-order terms. Our work provides a robust framework for
evaluating the thermal transport properties during structural transformation,
benefitting the future design of promising thermal and phononic materials and
devices
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