Version 2
Investigation of the rho-meson resonance with electron-positron colliding beams

Auslander, V.L. ; Budker, G.I. ; Pakhtusova, E.V. ; et al.
Yad.Fiz. 9 (1969) 114-119, 1969.
Inspire Record 57008 DOI 10.17182/hepdata.18687

None

2 data tables

Measured value of the pion form factor

Fitted peak cross section.


Version 2
Electromagnetic Pion Form-Factor in the Timelike Region

Barkov, L.M. ; Chilingarov, A.G. ; Eidelman, S.I. ; et al.
Nucl.Phys.B 256 (1985) 365-384, 1985.
Inspire Record 221309 DOI 10.17182/hepdata.6886

The pion electromagnetic form factor has been measured at the VEPP-2M collider in the c.m. energy range 360 MeV–1400 MeV with the detectors OLYA and CMD. On the basis of all available data for the pion form factor collected in the timelike region, the following values for ρ-meson parameters were obtained: m ρ = 775.9 ± 1.1 MeV, σ ρ = 150.5 ± 3.0 MeV. The ω-meson branching ratio into π + π − pair, electromagnetic radius of the pion, ππ scattering length in the P-wave and the strong interaction contribution to the muon ( g − 2) value were found to be B ωππ = (2.3 ± 0.4)%, 〈 r π 2 〉 = 0.422 ± 0.013 fm 2 , a 1 1 = 0.033 ± 0.033m π −3 , a H = (68.4 ± 1.1) × 10 −9 .

4 data tables

No description provided.

Experimental data from the OLYA detector

No description provided.

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Measurement of the $e^+e^- \to\pi^+\pi^- $ process cross section with the SND detector at the VEPP-2000 collider in the energy region $0.525<\sqrt{s}<0.883$ GeV

The SND collaboration Achasov, M.N. ; Baykov, A.A. ; Barnyakov, A.Yu. ; et al.
JHEP 01 (2021) 113, 2021.
Inspire Record 1789269 DOI 10.17182/hepdata.114983

The cross section of the process $e^+ e^-\to\pi^+\pi^-$ has been measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2000 $e^+e^-$ collider VEPP-2000 in the energy region $525 <\sqrt[]{s} <883$ MeV. The measurement is based on data with an integrated luminosity of about 4.6 pb$^{-1}$. The systematic uncertainty of the cross section determination is 0.8 % at $\sqrt{s}>0.600$ GeV. The $\rho$ meson parameters are obtained as $m_\rho = 775.3\pm 0.5\pm 0.6$ MeV, $\Gamma_\rho = 145.6\pm 0.6\pm 0.8$ MeV, $B_{\rho\to e^+ e^-}\times B_{\rho\to\pi^+\pi^-} = (4.89\pm 0.02\pm 0.04)\times 10^{-5}$, and the parameters of the $e^+ e^-\to\omega\to\pi^+\pi^-$ process, suppressed by $G$-parity, as $B_{\omega\to e^+ e^-}\times B_{\omega\to\pi^+\pi^-}= (1.32\pm 0.06\pm 0.02)\times 10^{-6} $ and $\phi_{\rho\omega} = 110.7\pm 1.5\pm1.0$ degrees.

3 data tables

The Born cross section of the process e+e- -> pi+pi- taking into account the radiative corrections due to the initial and final state radiation.

Measured value of the pion form factor

The bare e+e- -> pi+pi- undressed cross without vacuum polarization, but with the final state radiative correction.


Study of the process $e^+e^-\to n\bar{n}$ at the VEPP-2000 $e^+e^-$ collider with the SND detector

Achasov, M.N. ; Barnyakov, A.Yu. ; Beloborodov, K.I. ; et al.
Phys.Rev.D 90 (2014) 112007, 2014.
Inspire Record 1321689 DOI 10.17182/hepdata.71416

The process $e^+e^-\to n\bar{n}$ has been studied at the VEPP-2000 $e^+e^-$ collider with the SND detector in the energy range from threshold up to 2 GeV. As a result of the experiment, the $e^+e^-\to n\bar{n}$ cross section and effective neutron form factor have been measured.

2 data tables

The $e^+e^-\to n\bar{n}$ cross section ($\sigma_{n\bar{n}}$) and neutron effective form factor ($F_n$) measured in 2011. The quoted errors are statistical. The systematic error is 17$\%$ for the cross section and 9$\%$ for the form factor.

The $e^+e^-\to n\bar{n}$ cross section ($\sigma_{n\bar{n}}$) and neutron effective form factor ($F_n$) measured in 2012. The quoted errors are statistical. The systematic error is 17$\%$ for the cross section and 9$\%$ for the form factor. NOTE: corrected an apparent typo in paper for second-last data point (1990 $\to$ 1960) to make the numbers consistent with the plot in Figure 9.


Measurement of the e+e- -> K+K- process cross-section in the energy range s**(1/2) = 1.04 - 1.38 GeV with the SND detector in the experiment at VEPP-2M e+e- collider

Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
Phys.Rev.D 76 (2007) 072012, 2007.
Inspire Record 755881 DOI 10.17182/hepdata.51605

The cross section for the process $e^+e^- \to K^+K^-$ was measured in the energy range $\sqrt{s}$ = 1.04--1.38 GeV in the SND experiment at VEPP-2M $e^+e^-$ collider. The measured cross section is described by the Vector Meson Dominance model with contributions from the light vector mesons $\rho$, $\omega$, $\phi$ and their lowest excitations. The mean statistical accuracy of the measurement is 4.4 %, and the systematic uncertainty is 5.2 %.

1 data table

The measured cross section and charged kaon form factor.


Study of the process e+ e- --> pi+ pi- in the energy region 400-MeV < s**(1/2) < 1000-MeV.

Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
J.Exp.Theor.Phys. 101 (2005) 1053-1070, 2005.
Inspire Record 686349 DOI 10.17182/hepdata.41873

The cross section of the process e^+e^-\to \pi^+\pi^- was measured in the SND experiment at the VEPP-2M collider in the energy region 400<\sqrt[]{s}<1000 MeV. This measurement was based on about 12.4 \times 10^6 selected collinear events, which include 7.4\times 10^6 e^+e^-\to e^+e^-, 4.5\times 10^6 e^+e^-\to\pi^+\pi^- and 0.5\times 10^6 e^+e^-\to\mu^+\mu^- selected events. The systematic uncertainty of the cross section determination is 1.3 %. The \rho-meson parameters were determined: m_\rho=774.9\pm 0.4\pm 0.5 MeV, \Gamma_\rho=146.5\pm 0.8\pm 1.5 MeV, \sigma(\rho\to\pi^+\pi^-)=1220\pm 7\pm 16 nb as well as the parameters of the G-parity suppressed decay \omega\to\pi^+\pi^-: \sigma(\omega\to\pi^+\pi^-)=29.9\pm 1.4\pm 1.0 nb and \phi_{\rho\omega} = 113.5\pm 1.3\pm 1.7 degree.

3 data tables

Cross section taking into account the radiative corrections due to the initial and final state radiation.

Cross section and form factor after the radiative corrections have been undressed.

Undressed cross without vacuum polarization but with the final state radiation.


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.


Determination of form-factor parameters lambda+ and lambda0 in K(mu3) decay.

Artemov, V.M. ; Volkov, A.D. ; Emelyanenko, G.A. ; et al.
Phys.Atom.Nucl. 60 (1997) 218-223, 1997.
Inspire Record 404831 DOI 10.17182/hepdata.38592

None

1 data table

Formfactors F+ and F0 are parameterized as usual F+(0) = F(0)*(1 + CONST*(T/M(PI)**2)).