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Study of the process $e^+e^- \to π^+π^-π^0$ in the energy region $\sqrt[]{s}$ below 0.98 GeV

M. N. Achasov·K. I. Beloborodov·A. V. Berdyugin·A. G. Bogdanchikov·A. V. Bozhenok·A. D. Bukin·D. A. Bukin·T. V. Dimova·V. P. Druzhinin·V. B. Golubev·I. A. Koop·A. A. Korol·S. V. Koshuba·A. P. Lysenko·E. V. Pakhtusova·S. I. Serednyakov·V. V. Shary·Yu. M. Shatunov·Z. K. Silagadze·A. N. Skrinsky·A. A. Valishev·A. V. Vasiljev
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Abstract

The cross section of the process $e^+e^-\to π^+π^-π^0$ was measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the energy region $\sqrt[]{s}$ below 980 MeV. This measurement was based on about $1.2 \times 10^6$ selected events. The obtained cross section was analyzed together with the SND and DM2 data in the energy region $\sqrt[]{s}$ up to 2 GeV. The $ω$-meson parameters: $m_ω=782.79\pm 0.08\pm 0.09$ MeV, $Γ_ω=8.68\pm 0.04\pm 0.15$ MeV and $σ(ω\to 3π)=1615\pm 9\pm 57$ nb were obtained. It was found that the experimental data cannot be described by a sum of only $ω$, $ϕ$, $ω^\prime$ and $ω^{\prime\prime}$ resonances contributions. This can be interpreted as a manifestation of $ρ\to 3π$ decay, suppressed by $G$-parity, with relative probability $B(ρ\to 3π) = (1.01\pm^{0.54}_{0.36}\pm 0.034) \times 10^{-4}$.

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M. N. Achasov, K. I. Beloborodov, A. V. Berdyugin, A. G. Bogdanchikov, A. V. Bozhenok, A. D. Bukin, D. A. Bukin, T. V. Dimova, V. P. Druzhinin, V. B. Golubev, I. A. Koop, A. A. Korol, S. V. Koshuba, A. P. Lysenko, E. V. Pakhtusova, S. I. Serednyakov, V. V. Shary, Yu. M. Shatunov, Z. K. Silagadze, A. N. Skrinsky, A. A. Valishev, A. V. Vasiljev. 2003-05-19. Study of the process $e^+e^- \to π^+π^-π^0$ in the energy region $\sqrt[]{s}$ below 0.98 GeV. https://doi.org/10.1103/physrevd.68.052006

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