Measurement of the branching ratio and search for a CP violating asymmetry in the η→π+π−e+e− (γ ) decay at KLOE
- Ambrosino, F.
- Antonelli, A.
- Antonelli, M.
- Archilli, F.
- Beltrame, P.
- Bencivenni, G.
- Bertolucci, S.
- Bini, C.
- Bloise, C.
- Bocchetta, Simona
- Bossi, F.
- Branchini, Paolo
- Capon, G.
- Capussela, T.
- Ceradini, Filippo
- Ciambrone, P.
- Crucianelli, F.
- De Lucia, E.
- De Santis, A.
- De Simone, P.
- De Zorzi, G.
- Denig, A.
- Di Domenico, A.
- Di Donato, C.
- Di Micco, Biagio
- Dreucci, M.
- Felici, G.
- Fiore, S.
- Franzini, P.
- Gatti, C.
- Gauzzi, P.
- Giovannella, S.
- Graziani, Enrico
- Lanfranchi, G.
- Lee-Franzini, J.
- Leone, D.
- Martini, M.
- Massarotti, P.
- Meola, S.
- Miscetti, S.
- Moulson, M.
- Mueller, S.
- Murtas, F.
- Napolitano, M.
- Nguyen, Federico
- Palutan, M.
- Pasqualucci, E.
- Passeri, Antonio
- Patera, V.
- Perfetto, F.
- Santangelo, P.
- Sciascia, B.
- Spadaro, T.
- Testa, M.
- Tortora, Ludovico
- Valente, P.
- Venanzoni, G.
- Versaci, R.
- Xu, G.
DOIAbstract
We have studied the η→π+π−e+e− (γ ) decay using about 1.7 fb−1 collected by the KLOE experiment at the DA NE φ-factory. This corresponds to about 72 millions η mesons produced in φ radiative decays. We have measured the branching ratio, inclusive of radiative effects, with 4% accuracy: BR(η→ π+π−e+e− (γ )) = (26.8 ± 0.9Stat. ± 0.7Syst.) × 10−5. We have obtained the first measurement of the CPodd ππ–ee decay planes angular asymmetry, Aφ = (−0.6±2.5Stat. ±1.8Syst.)×10−2
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