We present a measurement of the doubly radiative decay η → π0γγ based on a sample of 82 million η mesons produced in the e+e− → ϕ → ηγ process at the Frascati ϕ-factory DAΦNE. From the data analysis, 1246 ± 133 signal events were observed. By normalising the signal to the well-known η → 3π0 decay the branching fraction is measured to be (0.98 ± 0.11stat ± 0.14syst) × 10−4. This result agrees with a preliminary KLOE measurement, but is a factor of two smaller than the current world average. Results for dΓ(η → π0γγ)/dM2(γγ) are also presented and compared with the latest theoretical predictions.
Measurement of η → π0γγ branching fraction with the KLOE detector
Punzi, L.;
2025
Abstract
We present a measurement of the doubly radiative decay η → π0γγ based on a sample of 82 million η mesons produced in the e+e− → ϕ → ηγ process at the Frascati ϕ-factory DAΦNE. From the data analysis, 1246 ± 133 signal events were observed. By normalising the signal to the well-known η → 3π0 decay the branching fraction is measured to be (0.98 ± 0.11stat ± 0.14syst) × 10−4. This result agrees with a preliminary KLOE measurement, but is a factor of two smaller than the current world average. Results for dΓ(η → π0γγ)/dM2(γγ) are also presented and compared with the latest theoretical predictions.File in questo prodotto:
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