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ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2000, vol. 475, p. 190-197

Cross section of the reaction e+e- → π+π-π+π- below 1 GeV at CMD-2

Akhmetshin R. R., Anashkin E. V., Arpagaus M., Aulchenko V. M., Banzarov V. Sh, Barkov L. M., Bashtovoy N. S., Bondar A. E., Bondarev D. V., Bragin A. V., Chernyak D. V., Eidelman S. I., Fedotovitch G. V., Gabyshev N. I., Grebeniuk A. A., Grigoriev D. N., Hughes V. W., Karpov S. V., Kazanin V. F., Khazin B. I., Koop I. A., Korostelev M. S., Krokovny P. P., Kurdadze L. M., Kuzmin A. S., Logashenko I. B., Lukin P. A., Mikhailov K. Yu, Milstein A. I., Nesterenko I. N., Okhapkin V. S., Otboev A. V., Polunin A. A., Popov A. S., Purlatz T. A., Root N. I., Ruban A. A., Ryskulov N. M., Shamov A. G., Shatunov Yu M., Shwartz B. A., Sibidanov A. L., Sidorov V. A., Skrinsky A. N., Smakhtin V. P., Snopkov I. G., Solodov E. P., Stepanov P. Yu, Sukhanov A. I., Thompson J. A., Titov V. M., Valishev A. A., Yudin Yu V., Zverev S. G.

Using 3.07 pb-1 of data collected in the energy range 0.60-0.97 GeV by CMD-2, about 150 events of the process e+e- → π+ π-π+π- have been selected. The energy dependence of the cross section agrees with the assumption of the a1(1260)π intermediate state which is dominant above 1 GeV. For the first time π+π-π+π- events are observed at the ρ meson energy. Under the assumption that all these events come from the ρ meson decay, the value of the cross section at the ρ meson peak corresponds to the following decay width: Γ(ρ0→π+π-π+π-) = (28 ± 1.4 ± 0.5) keV or to the branching ratio B(ρ0→π+π-π+π-) = (1.8 ± 0.9 ± 0.3)·10-5. (C) 2000 Published by Elsevier Science B.V.