Version 2
Measurement of the pion form factor in the energy range 1.04-GeV - 1.38-GeV with the CMD-2 detector.

The CMD-2 collaboration Aul'chenko, V.M. ; Akhmetshin, R.R. ; Banzarov, V.Sh. ; et al.
JETP Lett. 82 (2005) 743-747, 2005.
Inspire Record 712216 DOI 10.17182/hepdata.41807

The cross section for the process $e^+e^-\to\pi^+\pi^-$ is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 $e^+e^-$ events, 82000 $\mu^+\mu^-$ events, and 33000 $\pi^+\pi^-$ events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.

2 data tables

Measured value of the pion form factor with statistical errors only.

Measured value of the pion form factor


Version 2
Pion Form-factor Measurement in the Reaction $e^+ e^- \to \pi^+ \pi^-$ for Energies Within the Range From 0.4-{GeV} to 0.46-{GeV}

Vasserman, I.B. ; Ivanov, P.M. ; Kezerashvili, G.Ya. ; et al.
Yad.Fiz. 33 (1981) 709-714, 1981.
Inspire Record 167191 DOI 10.17182/hepdata.18823

None

1 data table

Measured value of the total E+ E- --> PI+ PI- cross section


Version 4
Measurement of the $\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^-$ Cross Section between 600 and 900 MeV Using Initial State Radiation

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Adlarson, P. ; et al.
Phys.Lett.B 753 (2016) 629-638, 2016.
Inspire Record 1385603 DOI 10.17182/hepdata.73898

In Phys. Lett. B 753, 629-638 (2016) [arXiv:1507.08188] the BESIII collaboration published a cross section measurement of the process $e^+e^-\to \pi^+ \pi^-$ in the energy range between 600 and 900 MeV. In this erratum we report a corrected evaluation of the statistical errors in terms of a fully propagated covariance matrix. The correction also yields a reduced statistical uncertainty for the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, which now reads as $a_\mu^{\pi\pi\mathrm{, LO}}(600 - 900\,\mathrm{MeV}) = (368.2 \pm 1.5_{\rm stat} \pm 3.3_{\rm syst})\times 10^{-10}$. The central values of the cross section measurement and of $a_\mu^{\pi\pi\mathrm{, LO}}$, as well as the systematic uncertainties remain unchanged.

10 data tables

Results of the BESIII measurement of the cross section $\sigma^{\rm bare}_{\pi^+\pi^-(\gamma_{\rm FSR})} \equiv \sigma^{\rm bare}(e^+e^-\rightarrow\pi^+\pi^-(\gamma_{\rm FSR}))$ and the squared pion form factor $|F_\pi|^2$. The errors are statistical only. The value of $\sqrt{s'}$ represents the bin center. The 0.9$\%$ systematic uncertainty is fully correlated between any two bins.

Results for the bare cross section $\sigma^\text{bare}_{\pi^+\pi^-}$ and the pion form factor together with their statistical uncertainties. The systematical uncertainties are given by 0.9% (see <a href="https://inspirehep.net/literature/1385603">arXiv:1507.08188</a>).

Bare cross section $\sigma^\mathrm{bare}(e^+e^-\to\pi^+\pi^-(\gamma_\mathrm{FSR}))$ of the process $e^+e^-\to\pi^+\pi^-$ measured using the initial state radiation method. The data is corrected concerning final state radiation and vacuum polarization effects. The final state radiation is added using the Schwinger term at born level.

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High-statistics measurement of the pion form factor in the rho-meson energy range with the CMD-2 detector

The CMD-2 collaboration Akhmetshin, R.R. ; Aulchenko, V.M. ; Banzarov, V.Sh. ; et al.
Phys.Lett.B 648 (2007) 28-38, 2007.
Inspire Record 728302 DOI 10.17182/hepdata.41782

We present a measurement of the pion form factor based on e+e- annihilation data from the CMD-2 detector in the energy range 0.6&lt;sqrt(s)&lt;1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five times larger than that used in our previous measurement.

2 data tables

Measured values of the pion form factor. The errors are statistical only.

Measured value of the bare PI+ PI- cross section including corrections for radiative effects but excluding corrections for vacuum polarization effects. The errors are statistical only.


Measurement of the e+e- -> pi+pi- cross section with the CMD-2 detector in the 370-520 MeV c.m. energy range

Aul'chenko, V.M. ; Akhmetshin, R.R. ; Banzarov, V.Sh. ; et al.
JETP Lett. 84 (2006) 413-417, 2006.
Inspire Record 728191 DOI 10.17182/hepdata.41786

The cross section of the process e+e- -> pi+pi- has been measured at the CMD-2 detector in the 370-520 MeV center-of-mass (c.m.) energy range. A systematic uncertainty of the measurement is 0.7 %. Using all CMD-2 data on the pion form factor, the pion electromagnetic radius was calculated. The cross section of muon pair production was also determined.

3 data tables

The measured Born muon pair production cross section. Errors are statistical only.

The measured pion form factor. The errors are statistical only.

The measured bare PI+ PI- production cross section. This is corrected for radiative effects but excludes a correction for vacuum polarization effects. The errors are statistical only.


Measurement of e+e- -> pi+pi- cross section with CMD-2 around rho-meson

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Arbuzov, A.B. ; et al.
Phys.Lett.B 527 (2002) 161-172, 2002.
Inspire Record 568807 DOI 10.17182/hepdata.27037

The cross section of the process e+e- -> pi+pi- has been measured using about 114000 events collected by the CMD-2 detector at the VEPP-2M e+e- collider in the center-of-mass energy range from 0.61 to 0.96 GeV. Results of the pion form factor determination with a 0.6% systematic uncertainty are presented. Implications for the hadronic contribution to the muon anomalous magnetic moment are discussed.

1 data table

Updated measured values of the pion form factor and 'bare' cross section.


Measurement of $e^+ e^- \rightarrow \pi^+ \pi^-$ cross-section with CMD-2 around $\rho$ meson

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Arpagaus, M. ; et al.
BUDKER-INP-1999-10, 1999.
Inspire Record 498859 DOI 10.17182/hepdata.50143

In experiments with the CMD-2 detector at the VEPP-2M electron-positron collider at Novosibirsk about 150000 $e^+e^-\to\pi^+\pi^-$ events were recorded in the center-of-mass energy range from 0.61 up to 0.96 GeV. The result of the pion form factor measurement with a 1.4% systematic error is presented. The following values of the $\rho$-meson and $\rho-\omega$ interference parameters were found: $M_\rho=(775.28\pm 0.61\pm 0.20) MeV, \Gamma_\rho=(147.70\pm 1.29 \pm 0.40) MeV, \Gamma(\rho\to e^+e^-)=(6.93\pm 0.11\pm 0.10) keV, Br(\omega\to\pi^+\pi^-) = (1.32\pm 0.23)%$.

1 data table

No description provided.


MEASUREMENT OF THE PION FORM-FACTOR NEAR THE THRESHOLD OF THE REACTION e+ e- ---> pi+ pi- WITH A TIME-OF-FLIGHT DETECTOR

Vasserman, I.B. ; Ivanov, P.M. ; Kezerashvili, G.Ya. ; et al.
SLAC-TRANS-0196, 1981.
Inspire Record 164524 DOI 10.17182/hepdata.37120

None

1 data table

RADIATIVE CORRECTIONS APPLIED.


Pion Form-Factor Measurement by e+ e- --> pi+ pi- in the Energy Range 2 e from 0.78-GeV Up to 1.34-GeV

Bukin, A.D. ; Vasserman, I.B. ; Koop, I.A. ; et al.
Phys.Lett.B 73 (1978) 226-228, 1978.
Inspire Record 134220 DOI 10.17182/hepdata.27474

The cross section of the reaction e + e − → π + π − has been measured in the energy range 2 E from 0.78 up to 1.34 GeV. The obtained experimental values of the pion form factor exceed notably the ρ -meson tail.

1 data table

No description provided.


MEASUREMENT OF PION FORM-FACTOR IN E+ E- ---> PI+ PI- REACTION NEAR PRODUCTION THRESHOLD. (IN RUSSIAN)

Vasserman, I.B. ; Kurdadze, L.M. ; Sidorov, V.A. ; et al.
Sov.J.Nucl.Phys. 30 (1979) 519, 1979.
Inspire Record 148297 DOI 10.17182/hepdata.18997

None

1 data table

RADIATIVE CORRECTIONS APPLIED.