1,723 research outputs found
Branching ratios, asymmetries and polarizations of decays
We analyzed the nonleptonic decays with by employing the perturbative QCD (PQCD) factorization
approach. Here the branching ratios, the asymmetries and the complete set
of polarization observables are investigated systematically. Besides the
traditional contributions from the factorizable and nonfactorizable diagrams at
the leading order, the next-to-leading order (NLO) vertex corrections could
also provide considerable contributions. The PQCD predictions for the branching
ratios of the decays are consistent
with the measured values within errors. As for decays, the branching ratios can reach the order of and could
be measured in the LHCb and Belle-II experiments. The numerical results show
that the direct asymmetries of the considered decays are very small. Thus
the observation of any large direct asymmetry for these decays will be a
signal for new physics. The mixing induced asymmetries in the neutral
modes are very close to , which suggests that these channels
can give a cross-check on the measurement of the Cabbibo-Kobayashi-Maskawa
(CKM) angle and . We found that the longitudinal polarization
fractions are suppressed to due to the large nonfactorizable
contributions. The magnitudes and phases of the two transverse amplitudes
and are roughly equal, which
is an indication for the approximate light quark helicity conservation in these
decays. The overall polarization observables of and
channels are also in good agreement with the
experimental measurements as reported by LHCb and BaBar. Other results can also
be tested by the LHCb and Belle-II experiments.Comment: 14 pages, 1 figure, 6 table
Preparation and In Vitro Drug Release Behavior of 1,10-Phenanthroline/β-cyclodextrin–poly (Glycidyl Methacrylate) Drug-Loaded Microspheres
In this study, novel star-shaped polymers of β-cyclodextrin (β-CD)–poly (glycidyl methacrylate) (PGMA) were prepared by atom transfer radical polymerization (ATRP), formed from GMA and β-CD. In addition, the structure, properties and hydrophilicity of the β-CD-PGMA polymers thus prepared were systematically analyzed. 1,10-phenanthroline monohydrate (Phen)/β-CD-PGMA drug-loaded microspheres were prepared by emulsion solvent evaporation. The optimum preparation conditions were determined by orthogonal tests. Analysis results indicated that the performance of star-shaped polymers of β-CD-PGMA clearly changes, resulting in the increase of the contact angle from 17° to 72.5°, and their thermal degradation temperature was enhanced from 260 °C to 401 °C. Moreover, β-CD-PGMA drug-loaded microspheres with a smooth, spherical surface were successfully prepared, and the drug-loading capacity and average particle size of drug-loaded microspheres were 26.67 % and 10 μm, respectively. Drug release tests indicated that the release behavior of β-CD-PGMA drug-loaded microspheres conformed to Higuchi release kinetics, which exhibited a significant drug delivery capability. The release rate and utilization of β-CD-PGMA were greater than that of β-CD, demonstrating that β-CD-PGMA was more suitable as a drug delivery material
Electron self-energy and effective mass in a single heterostructure
In this paper, we investigate the electron self-energy and effective mass in
a single heterostructure using Green-function method. Numerical calculations of
the electron self-energy and effective mass for GaAs/AlAs heterostructure are
performed. The results show that the self energy (effective mass) of electron,
which incorporate the energy of electron coupling to interface-optical phonons
and half three-dimension LO phonons, monotonically increase(decrease) from that
of interface polaron to that of 3D bulk polaron with the increase of the
distance between the position of the electron and interface.Comment: 10 pages, 2 figure
Quasi-two-body decays in the perturbative QCD approach
In this paper, we calculated the branching ratios of the quasi-two-body
decays
by employing the perturbative QCD (PQCD) approach. The contributions from the
-wave resonances , and were taken into
account. The two-pion distribution amplitude is
parameterized by the vector current time-like form factor to study
the considered decay modes. We found that (a) the PQCD predictions for the
branching ratios of the considered quasi-two-body decays are in the order of
, while the two-body decay rates are extracted from those for the
corresponding quasi-two-body decays; (b) the whole pattern of the pion form
factor-squared measured by the BABAR Collaboration could be
understood based on our theoretical results; (c) the general expectation based
on the similarity between and
decays are confirmed: is consistent with the measured
within errors; and (d) new ratios
and among the branching ratios of the
considered decay modes are defined and could be tested by future experiments.Comment: 10 pages, 3 figure
Quasi-two-body decays in the perturbative QCD approach
We study the quasi-two-body decays by employing
the perturbative QCD approach. The two-meson distribution amplitudes
\Phi_{K\pi}^{\text{P-wave}} are adopted to describe the final state
interactions of the kaon-pion pair in the resonance region. The resonance line
shape for the -wave component in the time-like form factor
is parameterized by the relativistic Breit-Wigner function. For
most considered decay modes, the theoretical predictions for their branching
ratios are consistent with currently available experimental measurements within
errors. We also disscuss some ratios of the branching fractions of the
concerned decay processes. More precise data from LHCb and Belle-II are
expected to test our predictions.Comment: 10 pages, 3 figures and 2 tables.To be published in EPJ
Observation and management of shallow anterior chamber after glaucoma surgery
AIM: To analyze the cause and management of shallow anterior chamber after glaucoma surgery.<p>METHODS: The cause and management of shallow anterior chamber after glaucoma surgery on 298 cases(462 eyes)were analyzed retrospectively.<p>RESULTS: In 298 cases(462 eyes), 99 eyes(21.4%)had shallow anterior chamber. In 358 eyes treated with trabeculectomy, 77 eyes(21.5%)had shallow anterior chamber. In 85 eyes treated with trabeculectomy+MMC(mitomycin C), 20 eyes(23.5%)had shallow anterior chamber. In 19 eyes treated with trabeculectomy combined with cataract phacoemulsification and intraocular lens implantation, 2 eyes(10.53%)had shallow anterior chamber. Shallow anterior chamber appeared at 1 day to 5 days postoperatively. Forty-two eyes(42.4%)were with excessive filtering, 6 eyes(6.1%)with malignant glaucoma, 29 eyes(29.3%)with choroidal detachment, 2 eyes(2.0%)with malignant glaucoma complicated by choroidal detachment. Of 99 eyes with shallow anterior chamber, anterior chamber of 79 eyes recovered treated by nonsurgical methods, 20 eyes treated by operation.<p>CONCLUSION: The common cause of shallow anterior chamber after glaucoma surgery was preoperative high intraocular pressure, inflammation, excessive filtering, conjunctival flap flushing and choroidal detachment. Most cases can be managed with nonsurgical methods. Surgical interference should be taken if necessary
Probing dark particles indirectly at the CEPC
When dark matter candidate and its parent particles are nearly degenerate, it
would be difficult to probe them at the Large Hadron Collider directly. We
propose to explore their quantum loop effects at the CEPC through the golden
channel process . We use a renormalizable toy model
consisting of a new scalar and a fermion to describe new physics beyond the
Standard Model. The new scalar and fermion are general multiplets of the
symmetry, and couple to the muon lepton through Yukawa
interaction. We calculate their loop contributions to anomalous
and couplings which can be applied to many new
physics models. The prospects of their effects at the CEPC are also examined
assuming a 0.002 accuracy in the cross section measurement
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