Observation of large CP violation and evidence for direct CP violation in B0-->pi(+)pi(-) decays.
We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value.
Abe
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K
High Energy Accelerator Research Organization (KEK), Tsukuba.
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Akemoto
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Banerjee
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Chen
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Chistov
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Chuvikov
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Cole
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Danilov
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Dragic
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Drutskoy
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Eidelman
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Eiges
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Enari
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Epifanov
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Flanagan
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Furukawa
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Gabyshev
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Hastings
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Hazumi
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Hou
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Hsiung
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Iijima
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Ikeda
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Inami
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Ishikawa
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Ishino
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Itoh
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Iwasaki
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Iwasaki
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Iwasaki
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Kakuno
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Kamitani
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Kataoka
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Kichimi
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Kikutani
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Kinoshita
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Koppenburg
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Krizan
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Kumar
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Kwon
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Lesiak
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Limosani
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Lin
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MacNaughton
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Mitaroff
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Miyata
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Murakami
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Natkaniec
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Neichi
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Ohuchi
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Oide
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Okabe
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Okuno
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Olsen
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Ostrowicz
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Ozaki
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Pakhlov
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Schümann
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Senyo
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Singh
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