ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 1999, vol. 462, p. 380-388

Study of the φ decays into π0π0γ and ηπ0γ final states

Akhmetshin R. R., Anashkin E. V., Arpagaus M., Aulchenko V. M., Banzarov V. S., Barkov L. M., Bashtovoy N. S., Bondar A. E., Bondarev D. V., Bragin A. V., Chernyak D. V., Dvoretsky A. S., Eidelman S. I., Fedotovich G. V., Gabyshev N. I., Grebeniuk A. A., Grigoriev D. N., Ivanov P. M., Karpov S. V., Kazanin V. F., Khazin B. I., Koop I. A., Krokovny P. P., Kurdadze L. M., Kuzmin A. S., Logashenko I. B., Lukin P. A., Lysenko A. P., Mikhailov K. Yu, Nesterenko I. N., Okhapkin V. S., Perevedentsev E. A., Panich E. 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., Titov V. M., Yudin Yu V., Zverev S. G., Thompson J. A.

Radiative decays of the φ meson have been studied using a data sample of about 19 million φ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From selected e+ e- → π0π0γ and e+e- → ηπ0γ events the following model independent results have been obtained: Br(φ → π0π0γ) = (0.92 ± 0.08 ± 0.06) × 10-4 for Mπ0π0 > 700 MeV, Br(φ → ηπ0γ) = (0.90 ± 0.24 ± 0.10) × 10-4. It is shown that the intermediate mechanism f0(980)γ dominates in the φ → π0π0γ decay and the corresponding branching ratio is Br(φ → f0(980)γ) = (2.90 ± 0.21 ± 1.54) × 10-4. The systematic error is dominated by the possible model uncertainty. Using the same data sample the upper limit has been obtained for the P- and CP-violating decay of η at 90% CL: Br(η → π0π0) < 4.3 × 10-4. © 1999 Published by Elsevier Science B.V. All rights reserved.