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Using 58 million $J/psi$ and 14 million $psi(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/psi$ and $psi(2S) to Lambda bar{Lambda} pi^0$ and $Lambda bar{Lambda} eta$ are measured, and the decays of $J/psi$ and $psi(2S)$ to $n K^0_S bar{Lambda}+c.c.$ are observed and measured for the first time. Finally, $R$ measurement data taken with the BESII detector at center-of-mass energies between 3.7 and 5.0 GeV are fitted to determine resonance parameters of the high mass charmonium states, $psi(3770)$, $psi(4040)$, $psi(4160)$, and $psi(4415)$. The Beijing Electron Collider is being upgraded to a two-ring collider (BEPCII) with a design luminosity of $1 times 10^{33}$cm$^{-2}$ s$^{-1}$ at 3.89 GeV and will operate between 2 and 4.2 GeV in the center of mass. With this luminosity, the new BESIII detector will beable to collect, for example, 10 billion $J/psi$ events in one year of running. BEPCII and BESIII are currently nearing completion, and commissioning of both is expected to begin in mid-2008.
We report the preliminary R values for all the 85 energy points scanned in the energy region of 2-5 GeV with the upgraded Beijing Spectrometer (BESII) at Beijing Electron Positron Collider (BEPC). Preliminary results from the J/psi data collected wit
BESIII experiment has collected about 20 fb$^{-1}$ luminosity data between $sqrt{s}=3.8$ and 4.7 GeV via $e^{+}e^{-}$ collision. In this talk, we present the recent $XYZ$ results at BESIII, including mass and width measurements of $Y(4220)$, search f
Hadron spectroscopy is one of the most important physics goals of BESIII. BESIII brings great opportunities to study the XYZ states of charmonium by directly producing the Y states up to 4.6 GeV. High statistics of charmonium decays collected at BESI
There are about 33, 6.5 and 1.0 pb$^{-1}$ of $e^+e^-$ annihilation data have been taken around the center-of-mass energies of $sqrt s=$ 3.773 GeV, at $sqrt s=$ 3.650 GeV and at $sqrt s=$ 3.6648 GeV, respectively, with the BES-II detector at the BEPC
We have updated our evaluation of the hadronic contribution to the running of the QED fine structure constant using the recent precise measurements of the e+e- annihilation at the center-of-mass (c.m.s.) energy region between 2.6 and 3.65 GeV perform