相关论文: R-values in Low Energy e^+e^- Annihilation
We have obtained measurements of the total cross section for e+e- annihilation into hadronic final states for 6 energy points (2.6, 3.2, 2.4, 3.55, 4.6, and 5.0 GeV) with the upgraded Beijing Spectrometer (BESII). We report preliminary…
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…
We report preliminary $R$ values for all 85 energy points scanned in the energy region of 2-5 GeV with the upgraded Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC). The typical uncertainty on the R values we…
The recent results of the CMD-2, SND, KLOE, and BABAR experiments on e+e- annihilation into hadrons at low energies are reviewed.
Using the upgraded Beijing Spectrometer (BESII), 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 $R$,…
Final results of the measurement of $R = \sigma(e^+e^- \to hadrons) /\sigma(e^+e^- \to \mu^+\mu^-)$ in the energy region from 2 to 5 GeV with the upgraded Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC) are…
Using a data sample with a total integrated luminosity of 10.0 pb$^{-1}$ collected at center-of-mass energies of 2.6, 3.07 and 3.65 GeV with BESII, cross sections for $e^+e^-$ annihilation into hadronic final states ($R$ values) are…
New results on the low energy e+ e- annihilation into hadrons from Novosibirsk and Beijing are described. Implications of the new measurements for the evaluation of the hadronic contribution to the muon anomalous magnetic moment are…
The values of $R = \sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$ for 85 center-of-mass energies between 2 and 5 GeV were measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider, with an average…
A method of measuring e+e- annihilation cross sections at low energy sqrt{s}< 5 GeV, using initial-state radiation, is described. Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass energy, obtained via ISR, are…
The current status of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E_0=400-1400 MeV and recent results of data analysis for $\phi$, $\omega$ and $\rho$ decays and e^+e^- annihilation into hadrons are…
Beijing Spectrometer (BES) at Beijing Electron Positron Collider (BEPC), IHEP has accumulated 2.5 $\times 10^7$ J/$\Psi$ and plans to increase the number to $10^8 \sim 10^9$ in the near future. In this paper I review and summarize the…
By analyzing the large-angle Bhabha scattering events $e^{+}e^{-}$ $\to$ ($\gamma$)$e^{+}e^{-}$ and diphoton events $e^{+}e^{-}$ $\to$ $\gamma\gamma$ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900…
A summary of results obtained from e^+e^- annihilations at LEP is given. The precision measurements around the Z resonance, the results from charged gauge boson production and searches for new particles are reviewed. Particular emphasis is…
BESIII is a new state-of-the-art 4$\pi$ detector at the upgraded BEPCII two-ring $\ee$ collider at the Institute of High Energy Physics in Beijing, China. It has been in operation since 2008, and has collected the world's largest data…
The Beijing $e^+e^-$-collider (BEPCII) is a double-ring symmetric collider running at center-of-mass energies between 2.0 and 4.6 GeV. This energy range allows the BESIII-experiment to measure baryon electromagnetic form factors in direct…
We report measurents of the continuum $R_{\rm uds}$ near the center-of-mass energy of 3.70 GeV, the $R_{{\rm uds(c)}+\psi(3770)}(s)$ and the $R_{\rm had}(s)$ values in $e^+e^-$ annihilation at 68 energy points in the energy region between…
$J/\Psi$ particles are abundantly produced at the Beijing Electron Positron Collider (BEPC). The $J/\Psi$ decays provide an excellent place for studying $N^*$ resonances. For $J/\Psi\to\bar NN\pi$ and $\bar NN\pi\pi$, the $\pi N$ and…
Using $5.2 \ \mathrm{fb}^{-1}$ $e^+ e^-$ annihilation data samples collected with the BESIII detector, we measure the cross sections of $e^+e^- \to K_S^0 K^\pm \pi^\mp \pi^0$ and $K_{S}^{0}K^{\pm}\pi^{\mp}\eta$ at center-of-mass energies…
We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow…