Study of the decay φ→π0π0γ with the KLOE detector

Radiative ϕ decays with derivative interactions

“…Interestingly, a destructive interference of f 0 (600) and f 0 (980) is also the outcome of Ref. [21], where the f 0 (980) channel overestimates the data below ∼ 700 MeV. Nevertheless a more refined analysis including the interference with the f 0 (600) meson and using the new data of KLOE [34] -for which at present no tables with branching ratios have been presented-will be compulsory and represents an outlook of the present work.…”

“…A destructive interference in the f 0 (600) channel should be invoked in order to get agreement with data, see also Ref. [21]. While leaving a more detailed study as an outlook, this fact can represent a significant constraint on models based on a particular interpretation of the scalar mesons, such as the tetraquark assignment.…”

“…Being the coupling to kaons of particular theoretical interest we perform the fit for different values of c f0KK . We start setting c f0KK = 0 ; the fit is done to the experimental data of SND and KLOE collaborations [20,21] corresponding to the black and grey dots in Fig. 3 retaining the data points above 0.6 GeV.…”

“…We thus not intend to state that c f0KK is small (what would be in conflict with data from ππ scattering) but only that its determination from the line shape is problematic when mechanism a.1 (whose amplitude is proportional to c f0ππ ) is regarded as dominant. We consider data sets from the SND and KLOE collaborations [20,21] corresponding respectively to the black and grey (green online) dots. The continuous line is the result of the fit by setting c f 0 KK = 0, the dashed line corresponds to the case c f 0 KK = 12 GeV −1 .…”

Radiative decays with scalar mesons and in Resonance Chiral Theory

“…The e + e − experiments in Novosibirsk [1,2] and Frascati [3,4] allow one to study the φ(1020) → ππγ (and πηγ) radiative decays. The invariant mass distributions of the pseudoscalar (P ) pairs in these decays are of considerable interest.…”