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
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.