325 research outputs found
Final state interactions in the decay
In this article, we study the final-state rescattering effects in the decay
, the numerical results indicate the corrections are
comparable with the contribution from the naive factorizable amplitude, and the
total amplitudes can accommodate the experimental data.Comment: 11 pages, 1 figure, revised version, to appear in EPJ
The newly observed open-charm states in quark model
Comparing the measured properties of the newly observed open-charm states
D(2550), D(2600), D(2750), D(2760), D_{s1}(2710), D_{sJ}(2860), and
D_{sJ}(3040) with our predicted spectroscopy and strong decays in a constituent
quark model, we find that: (1) the D(2\,^1S_0) assignment to D(2550) remains
open for its too broad width determined by experiment; (2) the D(2600) and
can be identified as the 2\,^3S_1-1\,^3D_1 mixtures; (3) if
the D(2760) and D(2750) are indeed the same resonance, they would be the
D(1\,^3D_3); otherwise, they could be assigned as the D(1\,^3D_3) and
, respectively; (4) the could be either the
's partner or the D_s(1\,^3D_3); and (5) both the
and interpretations for the seem likely. The
and radiative decays of these sates are also studied. Further
experimental efforts are needed to test the present quarkonium assignments for
these new open-charm states.Comment: 26 pages,7 figures, journal versio
The development of pharyngeal taste buds in Hucho taimen (Pallas, 1773) larvae
This study aims to investigate the relationship between the development of pharyngeal taste buds (TBs) and first feeding of Hucho taimen. Larvae were fed with live food (water flea and tubifex) for 8 weeks. TBs of larval pharynx were histologically examined using light microscopy during the rearing experiment. The results showed that the first few TBs primordia were visible within the pharynx 27 days after hatch (DAH), which coincides with the onset of feeding, and the first few TBs with open receptor areas appear 45 DAH. TBs of pharynx were well developed 76 DAH. The number and size of TBs were quantiïŹed during larval development. The average number of pharynx was 8.63±1.15, 11.29±0.50, 14.50±1.06, and 17.78±0.47 TBs at 27, 36, 45, and 76 DAH, respectively. The number of TBs increased in both the upper and lower pharynx. The ratio of height to width of TBs showed an increase tendency, ranging from 0.81 to 1.11. The height of TBs showed an increase tendency after 29 DAH during the development. However, the width of TBs exhibited a low at 35 DAH. In conclusion, the development of pharyngeal TBs coincides with the first feeding, and this should lead to a better understanding of improvement of larval rearing in H. taimen hatcheries
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
Study of
New data are presented on from a sample of 58M
events in the upgraded BES II detector at the BEPC. There is a
conspicuous signal for and a peak at higher mass which
may be fitted with . From a combined analysis with
data, the branching ratio
is at the 95%
confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.
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
Search for the Lepton Flavor Violation Processes and
The lepton flavor violation processes and are
searched for using a sample of 5.8 events collected with
the BESII detector. Zero and one candidate events, consistent with the
estimated background, are observed in and
decays, respectively. Upper limits on the branching ratios are determined to be
and at the 90% confidence level (C.L.).Comment: 9 pages, 2 figure
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