相关论文: Final R-value results from 2-5 GeV from BES and QC…

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…

We report 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 measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

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 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…

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…

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 are reported. Preliminary results using partial wave analysis for $J/\psi$ decays to $\gamma \pi^+ \pi^-$,…

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron Positron Collider II storage rings, the value of $R\equiv\sigma(e^{+}e^{-}\to$hadrons)/$\sigma(e^{+}e^{-}\to\mu^{+}\mu^{-})$ is…

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 $R$,…

Inclusive momentum spectra and multiplicity distributions of charged particles measured with BESII detector at center of mass energies of 2.2,2.6,3.0,3.2,4.6 and 4.8 GeV are presented. Values of the second binomial moment, $R_2$, obtained…

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…

R measurement results in 2--5 GeV region by BESII is reported in this talk. The study on $\sigma$ particle in $J/\psi \to \omega \pi^+ \pi^-$, based on $7.8 \times 10^6$ BESI $J/\psi$ data, is also reported.

Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been measured in the vicinity of the Psi(2S) resonance using the BESII detector operated at the BEPC. The Psi(2S) total width; partial widths to hadrons, pi+pi- J/Psi, muons;…

This presentation briefly summarizes the recent measurements of R-values in low energy e^+e^- annihilation. The new experiments aimed at reducing the uncertainties in R-values and performed with the upgraded Beijing Spectrometer (BESII) at…

The present work continues a series of the KEDR measurements of the $R$ value that started in 2010 at the VEPP-4M $e^+e^-$ collider. By combining new data with our previous results in this energy range we measured the values of…

Using data samples collected by the BESIII detector operating at the BEPCII storage ring, we measure the $e^+e^- \to K_{S}^{0}K^{\pm}\pi^{\mp}$ Born cross sections at center-of-mass energies between 3.8 and 4.6\,GeV, corresponding to a…

A comprehensive review of the measurements of $\tau$ lepton mass and $R$ values in the energy region between $2-5$ GeV, achieved at the BES experiment, is presented. In addition to the evaluation of their impact on the test of Standard…

Using photon conversions to e^+e^- pairs, the energy spectrum of inclusive photons from psi(2S) radiative decays is measured by BESII at the Beijing Electron-Positron Collider. The chi_{cJ}(1P) states (J=0,1,2) are clearly observed with…

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have determined the values of $R$ at thirteen points of the center-of-mass energy between 1.84 and 3.05 GeV. The achieved accuracy is about or better than $3.9\%$ at most of the…

BEPCII is a symmetric $e^+e^-$-collider located in Beijing running at center-of-mass energies between 2.0 and 4.6 GeV. This energy range allows the BESIII-experiment to measure hadron form factors both from direct $e^+e^-$-annihilation and…

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured the values of $R_{\text{uds}}$ and $R$ at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than…