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<sqrt(s)<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.


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


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 probability of the decay K+ ---> pi0 pi0 e+ neutrino

Barmin, V.V. ; Barylov, V.G. ; Davidenko, G.V. ; et al.
Sov.J.Nucl.Phys. 48 (1988) 1032-1034, 1988.
Inspire Record 457321 DOI 10.17182/hepdata.40034

None

1 data table

No description provided.


Analysis of the Cabibbo suppressed decay D0 --> pi- l+ nu.

The E687 collaboration Frabetti, P.L. ; Cheung, H.W.K. ; Cumalat, John P. ; et al.
Phys.Lett.B 382 (1996) 312-322, 1996.
Inspire Record 419904 DOI 10.17182/hepdata.42285

Results for the Cabibbo suppressed semileptonic decays D 0 → π − e + ν and D 0 → π − μ + ν (charge conjugates are implied) are reported by Fermilab photoproduction experiment E687. We find 45.4 ± 13.3 events in the electron mode and 45.6 ± 11.8 in the muon mode. The relative branching ratio BR (D 0 →π − l + v) BR (D 0 →K − l + v) for the combined sample is measured to be 0.101 ± 0.020 (stat.) ± 0.003 (syst.) 14 .

1 data table

CONST(C=V-CD and CONST(C=V-CS) are the Cabibbo-Kobayashi-Maskawa matrix elemets.


Measurement of B(D_s+ -> mu+ nu_mu)/B(D_s+ -> phi mu+ nu_mu) and Determination of the Decay Constant f_{D_s}

The Fermilab E653 collaboration Kodama, K. ; Torikai, S. ; Ushida, N. ; et al.
Phys.Lett.B 382 (1996) 299-304, 1996.
Inspire Record 420154 DOI 10.17182/hepdata.43789

We have observed $23.2 \pm 6.0_{-0.9}^{+1.0}$ purely-leptonic decays of $D_s^+ -> \mu^+ \nu_\mu$ from a sample of muonic one prong decay events detected in the emulsion target of Fermilab experiment E653. Using the $D_s^+ -> \phi \mu^+ \nu_\mu$ yield measured previously in this experiment, we obtain $B(D_s^+ --> \mu^+ \nu_\mu) / B(D_s^+ --> \phi \mu^+ \nu_\mu) =0.16 \pm 0.06 \pm 0.03$. In addition, we extract the decay constant $f_{D_s}=194 \pm 35 \pm 20 \pm 14 MeV$.

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)).


Measurement of the Form Factors for the Decay $D_s^+ \to \phi \mu^+ \nu$

The E687 collaboration Frabetti, P.L. ; Cheung, H.W.K. ; Cumalat, John P. ; et al.
Phys.Lett.B 328 (1994) 187-192, 1994.
Inspire Record 372405 DOI 10.17182/hepdata.42502

The fermilab high-energy photoproduction experiment E687 provides a sample of approximately 90 events of the decay mode D + s → φμ + ν . The ratios of the form factors governing the decay are measured to be R v =1.8±0.9±0.2 and R 2 = 1.1±0.8±0.1, implying a polarization of Г 1 /Г t = 1.0±0.5±0.1 for the electron decay, consistent with our measurement of the form factor for the decay D + → K ∗0 μ + ν .

1 data table

With a vetor meson in the final state, there are four formfactors, V(Q2), A1(Q2), A2(Q2), A3(Q2). Charge conjugated states are understood.