Experimental study of the e+e−→π0γ process in the energy region s=0.60–0.97 GeV

Ачасов, М. Н.; Beloborodov, K.; Berdugin, A.V.; Bogdanchikov, A. G.; Bozhenok, A. V.; Bukin, A. D.; Bukin, D.A.; Dimova, T.; Голубев, В. Б.; Ivanchenko, V. N.; Korol, A. A.; Koshuba, S. V.; Пахтусова, Е. В.; Polunin, A.A.; Pyata, E.E.; Salnikov, A.; Serednyakov, S. I.; Shary, V.; Shatunov, Yu. M.; Sidorov, V.; Силагадзе, З. К.; Skrinsky, A.N.; Skripkin, A. G.; Usov, Y.; Valishev, Alexander; Vasiljev, A. V.

doi:10.1016/s0370-2693(03)00336-8

Cited by 60 publications

(48 citation statements)

References 25 publications

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“…Without this assumption, B(φ → π 0 γ) is determined with about 20% uncertainty. The results presented in this paper supersede our previous measurement [3] based on a part of data collected by SND at VEPP-2M below 1 GeV.…”

Section: Discussionsupporting

confidence: 81%

“…5 in different energy regions in comparison with the previous most accurate measurements [2][3][4]. The obtained cross section is in reasonable agreement with the previous SND measurements [2,3], but is more precise. Above 0.76 GeV the CMD-2 and our data agrees within the 6% systematic uncertainty [4] for most data points.…”

Section: Fit To Cross Section Datasupporting

confidence: 89%

“…The accuracies of the products for the ρ and ω mesons are improved by a factor of about 2 compared with the most precise previous measurement by SND [3]. For the φ meson, our total uncertainty is about 20%.…”

Section: Discussionmentioning

confidence: 57%

“…The most accurate studies of the process e + e − → π 0 γ were performed in experiments at the VEPP-2M e + e − collider with the SND [2,3] and CMD-2 [4] detectors. From these data, only ω → π 0 γ decay has been measured with a relatively high accuracy.…”

Section: Introductionmentioning

confidence: 99%

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Study of the reactione+e−→π0γwith the SND detector at the VEPP-

et al. 2016

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The process e + e − → π 0 γ has been studied with the SND detector at the VEPP-2M e + e − collider. The e + e − → π 0 γ cross section has been measured in the center-of-mass energy range from 0.60 to 1.38 GeV. The cross section is well described by the vector meson dominance model. From the fit to the cross section data we have determined the branching fractions, and the relative phase between the ρ and ω amplitudes ϕρ = (−12.7 ± 4.5)• . Our data on the process e + e − → π 0 γ are the most accurate to date.

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Section: Discussionsupporting

confidence: 81%

Section: Fit To Cross Section Datasupporting

confidence: 89%

Section: Discussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

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Study of the reactione+e−→π0γwith the SND detector at the VEPP-

et al. 2016

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“…The quark model predictions for the phases of ω and φ mesons are 0 • and 180 • , respectively. The values close to those were obtained, for example, for the processes e + e − → 3π [7] and e + e − → π 0 γ [8]. The difference between the observed phases and quark model predictions of 0 • and 180 • for these processes can be described by φ − ω and ρ − ω mixing [7,9].…”

supporting

confidence: 83%

Reanalysis of thee+e−→ηγreaction cross section

et al. 2007

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In the experiment with the SND detector at the VEPP-2M e + e − collider measuring the e + e − → ηγ cross section in the energy range 0.6 < √ s < 1.38 GeV the reanalysis of data is performed. The goal is to improve the accuracy of the previous results by analysing ambiguities in the approximation of energy dependence of the e + e − → ηγ cross section, which were not taken into account in our previous study. We report new results on the approximation of the e + e − → ηγ cross section based on Vector Dominance Model under new model parameter assumptions. In our previous work [1] we performed a measurement of the e + e − → ηγ reaction cross section for two η-meson decay modes: η → 3π 0 and η → π + π − π 0 . The measured cross section was approximated within Vector Dominance Model (VDM). In this approximation the fact that with the free magnitudes and phases of all four ρ, ω, φ, and ρ ′ resonances, the minimized likelihood function has several minima and thus, a choice of the right minimization solution is ambiguous, was ignored. Additional physical restrictions must be applied to, at least, the parameters of the ρ ′ resonance, in order to make a right choice of the minimization solution.In this work the ρ ′ -meson parameters were estimated from the experimental data on the e + e − → ηρ cross section [2,3]. The cross section value in the ρ ′ -resonance maximum obtained from the approximation of the e + e − → ηρ cross section can be translated to the e + e − → ρ ′ → ηγ cross section using VDM as in Ref. [4]. The approximation of the data on the e + e − → ηρ cross section was done with three different models describing the energy dependence of the ρ ′ resonance width:Under these assumptions the resulting mass, width, and maximum cross section of the ρ ′ resonance varied within 1440-1520 MeV, 220-400 MeV, and 0.08-0.13 nb, respectively. All three ρ ′ parameter sets were used in the e + e − → ηγ cross section approximation. The difference in the experimental results was included in the systematic uncertainty of the final result. The cross section at the ρ ′ resonance maximum acquired an additional 20% systematic error from the uncertainty of the cross section calculation in the VDM.Natural values for the phase of the ρ ′ amplitude are 0 or 180 degrees. The phase shift from these values can be induced by the ρ and ρ ′ mixing via common decay channels, for example, ρ, ρ ′ → ωπ 0 . In the model considered in Ref. [5] it was shown that mixing is strongly energy dependent. For the approximation of the data on e + e − → ηγ cross section the ϕ ρ ′ value at the φ resonance maximum is important. Since at this energy the ρ − ρ ′ mixing is small, no significant phase shifts from 0 or 180 degrees are expected. Two approximations with the ϕ ρ ′ phase fixed at these values were considered. In order to estimate a corresponding systematic uncertainty of the approximation parameters due to the ρ ′ phase uncertainty, we varied ϕ ρ ′ by ±20 • with respect to its initial values.The fitting results with the ρ ′ parameters fixed to described ...

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Amsler¹

2018

The Quark Structure of Hadrons

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Experimental study of the e+e−→π0γ process in the energy region s=0.60–0.97 GeV

Cited by 60 publications

References 25 publications

Study of the reactione+e−→π0γwith the SND detector at the VEPP-

Study of the reactione+e−→π0γwith the SND detector at the VEPP-

Reanalysis of thee+e−→ηγreaction cross section

Su(3)

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