Based on an integrated luminosity of 1.61 fb−1e+e− collision data collected with the KLOE detector at DAΦNE, the Frascati ϕ-factory, a search for the P- and CP-violating decay η → π+π− has been performed. Radiative ϕ → ηγ decay is exploited to access the η mesons. No signal is observed in the π+π− invariant mass spectrum, and the upper limit on the branching fraction at 90% confidence level is determined to be ℬ(η → π+π−) < 4.9 × 10−6, which is approximately three times smaller than the previous KLOE result. From the combination of these two measurements we get ℬ(η → π+π−) < 4.4 × 10−6 at 90% confidence level.

Babusci, D., Berlowski, M., Bloise, C., Bossi, F., Branchini, P., Budano, A., et al. (2020). Upper limit on the η → π + π − branching fraction with the KLOE experiment. JOURNAL OF HIGH ENERGY PHYSICS, 2020(10) [10.1007/JHEP10(2020)047].

Upper limit on the η → π + π − branching fraction with the KLOE experiment

Ceradini F.;Di Cicco A.;Selce A.;
2020

Abstract

Based on an integrated luminosity of 1.61 fb−1e+e− collision data collected with the KLOE detector at DAΦNE, the Frascati ϕ-factory, a search for the P- and CP-violating decay η → π+π− has been performed. Radiative ϕ → ηγ decay is exploited to access the η mesons. No signal is observed in the π+π− invariant mass spectrum, and the upper limit on the branching fraction at 90% confidence level is determined to be ℬ(η → π+π−) < 4.9 × 10−6, which is approximately three times smaller than the previous KLOE result. From the combination of these two measurements we get ℬ(η → π+π−) < 4.4 × 10−6 at 90% confidence level.
Babusci, D., Berlowski, M., Bloise, C., Bossi, F., Branchini, P., Budano, A., et al. (2020). Upper limit on the η → π + π − branching fraction with the KLOE experiment. JOURNAL OF HIGH ENERGY PHYSICS, 2020(10) [10.1007/JHEP10(2020)047].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/374817
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