RADIATIVE f DECAYS: EXPERIMENTAL PROBLEMS

Experimental issues associated with measuring rare ∅ radiative decays at DAPHNE are discussed. We have studied by Monte Carlo simulation the detection of ∅→f₀γ, both for ∅→π⁰ π⁰ and ∅→π^+ π^-, in a minimal high precision spectrometer, CUSB. We find that, BR's as small as 1 x 10^-6 are measurable if all final particles are neutral, even assuming BR (∅→π⁰ π⁰ γ) is 10^-3, the experimental upper limit. We find, that the general purpose detector KLOE will achieve even higher accuracy, because of its hermeticity and fine segmentation. For ∅→π^+ π^-, we found that CUSB's sensitivity is limited to BR's of the order of 10^-5, whereas KLOE is sensitive to the smallest expected BR. We have included in the analysis the background process e^+ e^-→ϕ→ππγ, via a ρπ intermediate state. The matrix element and angular distributions for this process are given in the appendix. We also find that KLOE can measure the BR (ϕ→η'γ) down to ∼10^-6.