491 research outputs found
Wave functions and decay constants of and mesons in the relativistic potential model
With the decay constants of and mesons measured in experiment
recently, we revisit the study of the bound states of quark and antiquark in
and mesons in the relativistic potential model. The relativistic bound
state wave equation is solved numerically. The masses, decay constants and wave
functions of and mesons are obtained. Both the masses and decay
constants obtained here can be consistent with the experimental data. The wave
functions can be used in the study of and meson decays.Comment: more discussion added, to appear in EPJ
The ARGO-YBJ Experiment Progresses and Future Extension
Gamma ray source detection above 30TeV is an encouraging approach for finding
galactic cosmic ray origins. All sky survey for gamma ray sources using wide
field of view detector is essential for population accumulation for various
types of sources above 100GeV. To target the goals, the ARGO-YBJ experiment has
been established. Significant progresses have been made in the experiment. A
large air shower detector array in an area of 1km2 is proposed to boost the
sensitivity. Hybrid detection with multi-techniques will allow a good
discrimination between different types of primary particles, including photons
and protons, thus enable an energy spectrum measurement for individual specie.
Fluorescence light detector array will extend the spectrum measurement above
100PeV where the second knee is located. An energy scale determined by balloon
experiments at 10TeV will be propagated to ultra high energy cosmic ray
experiments
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
The pole in
Using a sample of 58 million events recorded in the BESII detector,
the decay is studied. There are conspicuous
and signals. At low mass, a large
broad peak due to the is observed, and its pole position is determined
to be - MeV from the mean of six analyses.
The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
The effect of oxygen stoichiometry on electrical transport and magnetic properties of La0.9Te0.1MnOy
The effect of the variation of oxygen content on structural, magnetic and
transport properties in the electron-doped manganites La0.9Te0.1MnOy has been
investigated. All samples show a rhombohedral structure with the space group .
The Curie temperature decreases and the paramagnetic-ferromagnetic (PM-FM)
transition becomes broader with the reduction of oxygen content. The
resistivity of the annealed samples increases slightly with a small reduction
of oxygen content. Further reduction in the oxygen content, the resistivity
maximum increases by six orders of magnitude compared with that of the
as-prepared sample, and the r(T) curves of samples with y = 2.86 and y = 2.83
display the semiconducting behavior () in both high-temperature PM phase and
low-temperature FM phase, which is considered to be related to the appearance
of superexchange ferromagnetism (SFM) and the localization of carriers. The
results are discussed in terms of the combined effects of the increase in the
Mn2+/(Mn2++Mn3+) ratio, the partial destruction of double exchange (DE)
interaction, and the localization of carriers due to the introduction of oxygen
vacancies in the Mn-O-Mn network.Comment: 20 pages, 8 figure
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
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