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arXiv · 0812.4830

Measurement of the branching ratio and search for a CP violating asymmetry in the eta -> pi+pi-e+e-(gamma) decay at KLOE

KLOE Collaboration·F. Ambrosino·A. Antonelli·M. Antonelli·F. Archilli·P. Beltrame·G. Bencivenni·S. Bertolucci·C. Bini·C. Bloise·S. Bocchetta·F. Bossi·P. Branchini·G. Capon·T. Capussela·F. Ceradini·P. Ciambrone·F. Crucianelli·E. De Lucia·A. De Santis·P. De Simone·G. De Zorzi·A. Denig·A. Di Domenico·C. Di Donato·B. Di Micco·M. Dreucci·G. Felici·S. Fiore·P. Franzini·C. Gatti·P. Gauzzi·S. Giovannella·E. Graziani·G. Lanfranchi·J. Lee-Franzini·D. Leone·M. Martini·P. Massarotti·S. Meola·S. Miscetti·M. Moulson·S. Müller·F. Murtas·M. Napolitano·F. Nguyen·M. Palutan·E. Pasqualucci·A. Passeri·V. Patera·F. Perfetto·P. Santangelo·B. Sciascia·T. Spadaro·M. Testa·L. Tortora·P. Valente·G. Venanzoni·R. Versaci·G. Xu
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Abstract

We have studied the eta->pi+pi-e+e-(gamma) decay using about 1.7 fb^-1 collected by the KLOE experiment at the DAFNE phi-factory. This corresponds to about 72 millions eta mesons produced in phi radiative decays. We have measured the branching ratio, inclusive of radiative effects, with 4% accuracy: BR(eta->pi+pi-e+e-(gamma)) = (26.8 +/- 0.9_Stat. +/- 0.7_Syst.) x 10^-5. We have obtained the first measurement of the CP-odd pipi-ee decay planes angular asymmetry, A_phi = (-0.6 +/- 2.5_Stat. +/- 1.8_Syst.) x 10^-2.

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KLOE Collaboration, F. Ambrosino, A. Antonelli, M. Antonelli, F. Archilli, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C. Bloise, S. Bocchetta, F. Bossi, P. Branchini, G. Capon, T. Capussela, F. Ceradini, P. Ciambrone, F. Crucianelli, E. De Lucia, A. De Santis, P. De Simone, G. De Zorzi, A. Denig, A. Di Domenico, C. Di Donato, B. Di Micco, M. Dreucci, G. Felici, S. Fiore, P. Franzini, C. Gatti, P. Gauzzi, S. Giovannella, E. Graziani, G. Lanfranchi, J. Lee-Franzini, D. Leone, M. Martini, P. Massarotti, S. Meola, S. Miscetti, M. Moulson, S. Müller, F. Murtas, M. Napolitano, F. Nguyen, M. Palutan, E. Pasqualucci, A. Passeri, V. Patera, F. Perfetto, P. Santangelo, B. Sciascia, T. Spadaro, M. Testa, L. Tortora, P. Valente, G. Venanzoni, R. Versaci, G. Xu. 2008-12-28. Measurement of the branching ratio and search for a CP violating asymmetry in the eta -> pi+pi-e+e-(gamma) decay at KLOE. https://doi.org/10.1016/j.physletb.2009.04.013

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