Study of the process $e^+e^-\to\eta\gamma$ in the center-of-mass energy range 1.07--2.00 GeV

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 90 (2014) 032002, 2014.
Inspire Record 1275333 DOI 10.17182/hepdata.62279

The $e^+e^-\to\eta\gamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $\eta\to 3\pi^0$, $\pi^0\to \gamma\gamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. The measured cross section of about 35 pb at 1.5 GeV is explained by decays of the $\rho(1450)$ and $\phi(1680)$ resonances.

2 data tables

The energy interval and E+ E- --> ETA GAMMA Born cross section(SIG). The first error in the cross section is statistical, the second systematic. For the last two energy intervals, the upper limits at the 90 PCT confidence level are listed for the cross section.

The fitted values of the cross sections at the resonance peaks.


Measurement of the eta and eta' transition form factors at q**2 = 112-GeV**2.

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Bona, M. ; et al.
Phys.Rev.D 74 (2006) 012002, 2006.
Inspire Record 716277 DOI 10.17182/hepdata.22085

We report a study of the processes e+e- -> eta gamma and e+e- -> etaprime gamma at a center-of-mass energy of 10.58 GeV, using a 232 fb^-1 data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20+6-5 eta gamma and 50+8-7 etaprime gamma events over small backgrounds, and measure the cross sections sigma(e+e- -> eta gamma) =4.5+1.2-1.1(stat)+-0.3(sys) fb and sigma(e+e- -> etaprime gamma)=5.4+-0.8(stat)+-0.3(sys) fb. The corresponding transition form factors at q^2 = 112 GeV^2 are q^2|F_eta(q^2)|=0.229+-0.030+-0.008 GeV, and q^2|F_etaprime(q^2)|=0.251+-0.019+-0.008 GeV, respectively.

3 data tables

Measured cross sections.

Undressed cross sections calculated by applying a 7.5 +- 0.2 PCT correction for vacuum polarization.

Transition form factors at Q**2 = 112 GeV**2.


Study of the Processes e+ e- --> eta gamma, e+ e- --> pi0 gamma --> 3 gamma in the c.m. Energy Range 600--1380 MeV at CMD-2

The CMD-2 collaboration Akhmetshin, R.R. ; Aulchenko, V.M. ; Banzarov, V.Sh. ; et al.
Phys.Lett.B 605 (2005) 26-36, 2005.
Inspire Record 658856 DOI 10.17182/hepdata.41864

The processes e+ e- --> eta gamma, e+ e- --> pi0 gamma --> 3 gamma have been studied in the c.m. energy range 600--1380 MeV with the CMD-2 detector. The following branching ratios have been determined: Br(rho --> eta gamma) = (3.21 +- 1.39 +- 0.20)x 10^{-4}; Br(omega --> eta gamma) = (4.44 + 2.29 -1.83 +- 0.28)x 10^{-4}; Br(phi --> eta gamma) = (1.373 +- 0.014 +- 0.085)x 10^{-2}; Br(rho --> pi0 gamma) = (6.21 +1.28 - 1.18 +- 0.39)x 10^{-4}; Br(omega --> pi0 gamma) = (9.06 +- 0.20 +- 0.57)x 10^{-2}; Br(phi --> pi0 gamma) = (1.258 +- 0.037 +- 0.077)x 10^{-3};

2 data tables

Born cross section for the process E+ E- --> ETA GAMMA.

Born cross section for the process E+ E- --> PI0 GAMMA.


New Measurements with the Orsay electron-Positron Storage Ring of the Radiative Decay Modes of the phi-Meson

Cosme, G. ; Courau, A. ; Dudelzak, B. ; et al.
Phys.Lett.B 63 (1976) 352-356, 1976.
Inspire Record 99833 DOI 10.17182/hepdata.27640

The radiative decay models of the φ-meson have been studied: e + e − → φ → ηγ →3 γ ; e + e − → φ → π o γ →3 γ . Cross sections σ φ → ηγ →3 γ and σ φ → π o γ →3 γ have been measured at five energies in the φ-meson energy region and clearly show the φ-resonance in the ηγ → 3 γ mode as well as in the π o γ → 3 γ mode. From a Breit-Wigner fit to the experimental data the values of the branching ratios are deduced: B φ → ηγ = (1.5 ± 0.4) × 10 −2 ; B φ → π o γ = (1.4 ± 0.5) × 10 −3 .

1 data table

REMOVING RADIATIVE CORRECTIONS, THE PHI PEAK CROSS SECTIONS ARE 66 NB +- 25 PCT <ETA GAMMA> AND 6.5 NB +- 30 PCT <PI0 GAMMA>.


Study of the Process e+ e- ---> eta gamma in c.m. Energy Range 600-1380 MeV at CMD-2

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Aulchenko, V.M. ; et al.
Phys.Lett.B 509 (2001) 217-226, 2001.
Inspire Record 554522 DOI 10.17182/hepdata.27025

The cross section of the process e+ e- ---> eta gamma has been measured in the 600-1380 MeV c.m. energy range with the CMD-2 detector. The following branching ratios have been determined: B(rho ---> eta gamma) = (3.28 +- 0.37 +- 0.23) 10^{-4}, B(omega ---> eta gamma) = (5.10 +- 0.72 +- 0.34) 10^{-4}, B(phi --> eta gamma) = (1.287 +- 0.013 +- 0.063) 10^{-2}. Evidence for the rho'(1450) ---> eta gamma decay has been obtained for the first time.

1 data table

The measured Born cross section for the ETA GAMMA final state.