Measurement of PHI-meson radiative decays at the storage ring VEPP-2M with the neutral detector

Results of the first experiments with the Neutral Detector at the electron-positron storage ring VEPP-2M are presented. Branching ratios of the PHI-meson radiative decays have been measured: B(PHI -> etaγ) = (1.30 +- 0.06)%, B(PHI -> π0γ) = (0.130 +- 0.013)%, their accuracy being several times higher than the world average. The width ratio is GAMMA(PHI -> etaγ)/GAMMA(PHI -> π0γ) = (10 +- 1). Using the above mentioned quantities, the ω-PHI mixing angle THETAsub(v) = (38.3 +- 0.2)0, as well as the ratio between the effective magnetic moments of the s- and u-quarks, μsub(s)/μsub(u) = (0.57 +- 0.03) have been calculated. (orig.)