Omega-neutral production by e-plus e-minus annihilation

Augustin, J.E. ; Benaksas, D. ; Buon, J. ; et al.
Phys.Lett.B 28 (1969) 513-516, 1969.
Inspire Record 56682 DOI 10.17182/hepdata.29065

The reaction e + e − → ω o has been measured by detecting the charged pions of the π + π − π o decay mode of the ω o. A partial decay width of ω o in e + e − : Γ e + e − =0.94±0.18 keV is deduced from this result.

1 data table

FITTED, BACKGROUND SUBTRACTED, PEAK OMEGA CROSS SECTION, CORRECTED FOR UNOBSERVED DECAYS, IS 1.82 +- 0.34 MUB. TABULATED ASSUMING CENTRAL ENERGY IS 782.6 MEV. VACUUM POLARIZATION AND RADIATIVE CORRECTIONS APPLIED.


Omega production by e+ e- annihilation

Benaksas, D. ; Cosme, G. ; Jean-Marie, B. ; et al.
Phys.Lett.B 42 (1972) 507-510, 1972.
Inspire Record 84977 DOI 10.17182/hepdata.28178

A large solid angle detector has been used to observe π + π − π 0 events produced, at the ω energy, by electron-positron collisions in the ORSAY storage ring. From the ω excitation curve we have deduced: σ ( e + e − → ω 3 π ) = (180 ± 0.20) μ b, Γ = (9.1 ± 0.8) MeV and with B( ω → π + π − π 0 ) = 0.898 ± 0.045 we have calculated Γ e + e − = (0.76 ± 0. 08) keV and g 2 ω 4π = 18.4 ± 1.8 .

2 data tables

EXPERIMENTAL CROSS SECTION INCLUDING RADIATIVE EFFECTS.

FITTED CROSS SECTION AT OMEGA PEAK, RADIATIVELY CORRECTED.


Pion Form-Factor from 480-MeV to 1100-MeV

Quenzer, A. ; Ribes, M. ; Rumpf, F. ; et al.
Phys.Lett.B 76 (1978) 512-516, 1978.
Inspire Record 134061 DOI 10.17182/hepdata.27443

The pion form factor is measured in the reaction e + e − → π + π − for center of mass energies in the range 480–1100 MeV. Our results are first analysed in terms of the conventional Vector Meson Dominance formalism, and then taking into account the ωπ inelastic channel. The result of this later formalism is a pion form factor ( F π ) which fits quite well all the existing data on F π both in the timelike and spacelike regions, and pion mean square radius of 〈 r π 2 〉 = 0.460 ± 0.011 fm 2 or 〈r π 2 〉 1 2 = 0.678 ± 0.008 fm .

1 data table

No description provided.


Cross-section of the Reaction $e^+ e^- \to \pi^+ \pi^- \pi^0$ for Center-of-mass Energies From 750-{MeV} to 1100-{MeV}

Cordier, A. ; Delcourt, B. ; Eschstruth, P. ; et al.
Nucl.Phys.B 172 (1980) 13-24, 1980.
Inspire Record 140174 DOI 10.17182/hepdata.34511

We present the results obtained with the magnetic detector DM1 at the Orsay storage ring ACO for the reaction e + e − → π + π − π 0 from 483 to 1100 MeV in the center of mass. Our data show without ambiguity an interference effect between the ω and φ mesons, which corresponds to a negative coupling constant product ratio Re( g γω g ω →3 π / g γφ g φ →3 π ) ; however our measurements above the φ, performed using kinematical analysis, can only be explained by a higher energy contribution. In addition, the parameters of the ω have been obtained with an improved accuracy compared to other experiments, and particularly the branching ratio B ω →e + e − = (6.75±0.69) × 10 −5 . We confirm that the reaction e + e − → π + π − π 0 proceeds essentially via a quasi-two-body state ϱπ , at the energy of the φ.

1 data table

FITTED CROSS SECTION AT OMEGA PEAK IS 1410 +- 130 NB AND AT PHI PEAK IS 615 +- 55 NB.