Radiative decay of ρ0 and φ mesons in a chiral unitary approach

Abstract

We study the ρ 0 and φ decays into π + π − γ, π 0 π 0 γ and φ into π 0 ηγ using a chiral unitary approach to deal with the final state interaction of the MM system. The final state interaction modifies only moderately the large momenta tail of the photon spectrum of the ρ 0→ π + π − γ decay. In the case of φ decay the contribution to π + π − γ and π 0 π 0 γ decay proceeds via kaonic loops and gives a distribution of ππ invariant masses in which the f 0(980) resonance shows up with a very distinct peak. The spectrum found for φ→ π 0 π 0 γ decay agrees with the recent experimental results obtained at Novosibirsk. The branching ratio for φ→ π 0 ηγ, dominated by the a 0(980), is also in agreement with recent Novosibirsk results.