Bepcii and Besiii
The Beijing Electron Collider has been upgraded (BEPCII) to a two-ring collider with a design luminosity of $1 \times 10^{33}$cm$^{-2}$ s$^{-1}$ at a center-of-mass energy of 3.78 GeV. It will operate between 2 and 4.6 GeV in the center of mass. With this luminosity, the BESIII detector will be able to collect, for example, 10 billion $J/\psi$ events in one year of running. This will be a unique facility in the world opening many physics opportunities. BEPCII and BESIII are both currently being commissioned, first events have been obtained, and data taking will take place in fall 2008.
Measurement of the total cross section for hadronic production by e(+)e(-) annihilation at energies between 2.6-5 GeV
Using the upgraded Beijing Spectrometer, we have measured the total cross section for e(+)e(-) annihilation into hadronic final states at center-of-mass energies of 2.6, 3.2, 3.4, 3.55, 4.6, and 5.0 GeV. Values of R, sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->&mgr;(+)&mgr;(-)), are determined.
Improved determination of the hadronic contribution to the muon (
${g-2}$) and to 
${\alpha(M_{\mathrm Z}^2)}$ Using new data from hadronic 
$\tau$ decays
Abstract. We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon 
$(g-2)$ and to the running of the QED fine structure constant 
$\alpha (s)$ at 
$s=M_{\mathrm Z}^2$. We incorporated new data from hadronic 
$\tau$ decays, recently published by the ALEPH Collaboration. In addition, compared to previous analyses, we use more extensive 
$e^+e^-$ annihilation data sets. The integration over the total hadronic cross section is performed using experimental data up to 40 GeV and results from perturbative QCD above 40 GeV. The improvement from 
$\tau$ data concerns mainly the pion form factor, where the uncertainty in the corresponding integral could be reduced by more than a factor of two. We obtain for the lowest order hadronic vacuum polarization graph 
$a^{\rm had}_\mu =(695.0\pm 15.0)\times10^{-10}$ and 
$\Delta \alpha ^{(5)}_{\rm had} (M^2_{\rm Z}) =(280.9 \pm 6.3) \times 10^{-4}$ using 
$e^+e^-$ data only. The corresponding results for combined 
$e^+e^-$ and 
$\tau$ data are 
$a^{\rm had}_\mu=(701.1 \pm 9.4)\times 10^{-10}$ and 
$\Delta \alpha ^{(5)}_{\rm had} (M^2_{\rm Z}) =(281.7 \pm 6.2) \times10^{-4}$, where the latter is calculated using the contribution from the five lightest quarks.
