Higher meson resonances in $ρ\to π^0 π^0 γ$ and $ω\to π^0 π^0 γ$

Abstract

The role of higher meson resonances with spin 1 and 2 is investigated quantitatively in the decay processes of $ρ\to π^0π^0 γ$ and $ω\to π^0 π^0 γ$. Among the higher resonances, we find that the $f_2(1270)$ tensor meson can give a nontrivial contribution especially to the $ω\to π^0 π^0 γ$ decay process. When the $f_2$ contribution is combined with the processes involving the vector and scalar meson intermediate states, a good agreement with the recent measurements is achieved for both decays. The effect of the $f_2(1270)$ is found to be sizable at the intermediate photon energies and may be verified by precise measurements of the recoil photon spectrum of the $ω\to π^0 π^0 γ$ decay. The dependence of the decay widths on various models for the $ρ$-$ω$ mixing in the literature is also investigated.