Analysis of the nature of the φ→γπη and φ→γπ0π0 decays -: art. no. 094007

We study interference patterns in the phi-->(gammaa(0) + pi (0)rho)-->gamma pi eta and phi-->(gammaf(0) + pi (0)rho)-->gamma pi (0)pi (0) reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the pi (0)eta spectrum in the decay phi-->gamma pi eta everywhere over the energy region and does not distort the pi (0)pi (0) spectrum in the decay phi-->gamma pi (0)pi (0) in the wide region of the pi (0)pi (0) system invariant mass, m(pi pi)>670 MeV, or when the photon energy is less than 300 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are reasonable arguments in favor of the one-loop mechanism phi -->K+K--->gammaa(0) and phi-->K+K- -->gammaf(0). We discuss also distinctions between the four-quark, molecular, and two-quark models and argue that the Novosibirsk data give evidence in favor of the four-quark nature of the scalar a(0)(980) and f(0)(980) mesons.