651 research outputs found
Study of f_0(980) and f_0(1500) from B_s \to f_0(980)\pi, f_0(1500)\pi Decays
In this paper, we analyze the scalar mesons and from
the decays within Perturbative
QCD approach. From the leading order calculations, we find that (a) in the
allowed mixing angle ranges, the branching ratio of is about , which is smaller than
that of (the difference is a few times even one
order); (b) the decay is better to distinguish
between the lowest lying state or the first excited state for ,
because the branching ratios for two scenarios have about one-order difference
in most of the mixing angle ranges; and (c) the direct CP asymmetries of for two scenarios also exists great difference. In
scenario II, the variation range of the value according to the mixing angle is very small, except for
the values corresponding to the mixing angles being near or
, while the variation range of in scenario I is very large. Compared with the future data for
the decay , it is ease to determine the nature
of the scalar meson .Comment: 16 pages, 3 figures, Revte
Effect of the Interfacial Transition Zone on Basic Mechanical Properties of a Solid Composite Propellant
The evaluation of basic mechanical properties are shown to be of importance for the solid composite propellant development and application. The numerical analysis approach termed the three-phase Voronoi cell finite element method, was proposed to evaluate of the interfacial transition zone effect. Numerical results showed that the performance of the effective modulus could be essentially enhanced by increasing the zone thickness. The module of the composite with the inhomogeneous zone was higher than that of the composite with the homogeneous one. The effect of different zones on volume fractions and matrix moduli was also calculated. The Voronoi method can also be helpful for analyzing the characteristic properties of other three-phase composites.Определение основных механических характеристик играет важную роль в разработке и применении композитного твердого ракетного топлива. Предложен численный метод, получивший название “трехфазный метод конечных элементов ячейки Вороного”, для оценки влияния зоны межфазного перехода. Численные результаты показывают, что эффективный модуль можно улучшить, увеличив толщину зоны межфазного перехода. Модуль композита с неоднородной зоной межфазного перехода выше такового с однородной зоной межфазного перехода. Рассчитано влияние различных зон межфазного перехода на объемные доли и модули матрицы. Для анализа характеристических свойств других трехфазных композитов также можно использовать трехфазный метод конечных элементов ячейки Вороного
The open-charm radiative and pionic decays of molecular charmonium Y(4274)
In this work, we investigate the decay widths and the line shapes of the
open-charm radiative and pionic decays of Y(4274) with the
molecular charmonium assignment. Our calculation
indicates that the decay widths of and
can reach up to 0.05 keV and 0.75 keV,
respectively. In addition, the result of the line shape of the photon spectrum
of shows that there exists a very sharp
peak near the large end point of photon energy. The line shape of the pion
spectrum of is similar to that of the pion
spectrum of , where we also find a very
sharp peak near the large end point of pion energy. According to our
calculation, we suggest further experiments to carry out the search for the
open-charm radiative and pionic decays of Y(4274).Comment: 7 pages, 6 figures, 1 table. Published versio
Nutrigenomic and nutritional analyses reveal the effects of pelleted feeds on Asian Seabass (Lates calcarifer)
As nutrition-related expenses constitute the majority of the costs for aquaculture farms, it is essential for them to use feeds that provide an ideal combination of nutrients for the species of choice. In this study, the relative effect of consuming three different pelleted feeds (B, C and D) in comparison to frozen baitfish (A; control) were compared on juvenile Asian seabass (77.3 ± 22.4g) that were selected for increased growth rate over two generations. Our objectives were: 1) to evaluate the effects of different pelleted feeds based on overall physiological changes and nutritional quality of fillets; 2) improve our understanding of the underlying mechanisms with transcriptomic analysis; 3) if possible, identify the feed type that supports the growth of these fishes without substantially reducing the nutritional quality of fillet. The growth performance, fatty acid composition of fillet, hepatic histology and transcriptome of the fishes (Groups A-D) were analyzed. The majority of fatty acids of the fillets, except γ-linolenic acid (GLA, C18:3n6), correlated significantly with the respective diets. Asian seabass fed Feed C showed highest specific growth rate (SGR) and feed conversion efficiency (FCE) with closest histology and transcriptomic profile to control, but their fillet contained the highest n6/n3 ratio. When the liver-based transcriptomes were analyzed, a complex set of differentially expressed genes were detected between groups fed pelleted feeds and controls as well as among the pellet-fed groups themselves. Significant enrichment of genes with growth-related function tallied with the morphological data measured. When compared with control (Group A), ‘Biosynthesis of unsaturated fatty acids’ and ‘Steroid biosynthesis’ pathways were significantly enriched in pellet-fed groups. Reduced goblet cell numbers were observed in the gut of pellet-fed fish compared to controls and fads6 was found to be a suitable candidate gene to separate wild-caught Asian seabass, from pellet-fed ones. These results provide insights for researchers on the various effects of feeds on the biochemistry and global gene expression of the fish and potentially for seabass farms to make more informed feed choices
Angle-resolved photoemission in doped charge-transfer Mott insulators
A theory of angle-resolved photoemission (ARPES) in doped cuprates and other
charge-transfer Mott insulators is developed taking into account the realistic
(LDA+U) band structure, (bi)polaron formation due to the strong electron-phonon
interaction, and a random field potential. In most of these materials the first
band to be doped is the oxygen band inside the Mott-Hubbard gap. We derive the
coherent part of the ARPES spectra with the oxygen hole spectral function
calculated in the non-crossing (ladder) approximation and with the exact
spectral function of a one-dimensional hole in a random potential. Some unusual
features of ARPES including the polarisation dependence and spectral shape in
YBa2Cu3O7 and YBa2Cu4O8 are described without any Fermi-surface, large or
small. The theory is compatible with the doping dependence of kinetic and
thermodynamic properties of cuprates as well as with the d-wave symmetry of the
superconducting order parameter.Comment: 8 pages (RevTeX), 10 figures, submitted to Phys. Rev.
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
Measurements of the Mass and Full-Width of the Meson
In a sample of 58 million events collected with the BES II detector,
the process J/ is observed in five different decay
channels: , , (with ), (with
) and . From a combined fit of all five
channels, we determine the mass and full-width of to be
MeV/ and
MeV/.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
Study of and from and Decays
We use the decay modes and to
study the scalar mesons and within perturbative QCD
framework. For , we perform our calculation in two
scenarios of the scalar meson spectrum. The results indicate that scenario II
is more favored by experimental data than scenario I. The important
contribution from annihilation diagrams can enhance the branching ratios about
50% in scenario I, and about 30% in scenario II. The predicted branching ratio
of in scenario I is also less favored by the experiments.
The direct CP asymmetries in are small, which are
consistent with the present experiments.Comment: More references are added. Published Versio
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