Measurement of the DirectCPAsymmetry inB¯→Xs+dγDecays with a Lepton Tag

L Pesántez,G Schnell,U Tamponi,J Haba,T Aushev,T Kumita,T Sanuki,S Yashchenko,O Seon,J Yamaoka,V Savinov,D Getzkow,S Eidelman,E Ribežl,T Sumiyoshi,A Kuzmin,M Starič,K Inami,H Park,V Bansal,Z Drásal,V Gaur,N Gabyshev,I Adachi,G Bonvicini,R Itoh,B Bhuyan,Y Choi,D Červenkov,B Golob,Y Teramoto,P Vanhoefer,A Garmash,A Drutskoy,T Ferber,T Uglov,G Pakhlova,T Iijima,Y Iwasaki,Y Sakai,D Cinabro,Y Li,S Ogawa,O Frost,T Kawasaki,T Julius,P Krokovny,S Al Said,J Hasenbusch,O Schneider,M Steder,V Bhardwaj,J Dalseno,A Zupanc,K Arinstein,Y Yook,C Schwanda,V Vorobyev,K Chilikin,Y Watanabe,R Pestotnik,M Bračko,T Kuhr,J Libby,E Kato,S Sandilya,M Nayak,S Uno,K Miyabayashi,S Okuno,Z Doležal,P Križan,V Chobanova,E Solovieva,Z Natkaniec,S Korpar,P Pakhlov,H Hayashii,A Ishikawa,K Adamczyk,M Uchida,D Liventsev,G Tatishvili,C Oswald,H Miyata,R Chistov,Y Usov,A Vinokurova,M Huschle,B Shwartz,A Rostomyan,D Matvienko,E Won,R Gillard,C Kiesling,A Abdesselam,A Bobrov,V Chekelian,R Ayad,H Farhat,R Mizuk,K Senyo,L Li Gioi,A Chen,D Joffe,M Nakao,E Nakano,S Nishida,A Moll,K Trabelsi,B Kronenbitter,Y Unno ,G B Mohanty ,A Sibidanov ,T Horiguchi ,I Jaeglé ,F Simon ,J S Lange ,P Kodyš ,M Ritter ,S H Kim ,H Aihara ,W.-S Hou ,M J Kim ,V Shebalin ,D Dutta ,Y M Goh ,T Nanut ,A J Schwartz ,N K Nisar ,B R Ko ,S L Olsen ,S Ganguly ,T A Shibata ,Andreas Heller ,P Urquijo ,J H Kim ,M Petrič ,K H Kang ,J G Shiu ,V Zhilich ,C R Ng ,D Y Kim ,Z P Zhang ,L Šantelj ,L E Piilonen ,I S Lee ,A Bondar ,C Van Hulse ,E Barberio ,A M Bakich ,Y S Sohn ,Y Sato ,A Bożek ,J Dingfelder ,G Varner ,D M Asner ,V Aulchenko ,C P Shen ,M Z Wang ,P Wang ,P Lukin ,B Wang ,S Bahinipati ,X He ,C H Wang ,T K Pedlar ,Y J Kim ,M N Wagner ,T E Browder ,M Różańska ,K M Williams ,V Zhulanov ,C W Park ,M E Sevior ,J B Kim ,J E Fast ,Y.-J Kwon ,N Taniguchi ,H K Moon ,A Sokolov ,B G Cheon ,K T Kim ,K Cho

doi:10.1103/physrevlett.114.151601

Abstract

We report the measurement of the direct CP asymmetry in the radiative B¯→X(s+dγ) decay using a data sample of (772 ± 11)×10(6) BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The CP asymmetry is measured as a function of the photon energy threshold. For Eγ*≥2.1 GeV, where Eγ* is the photon energy in the center-of-mass frame, we obtain A(CP)(B¯→X(s+dγ))=(2.2±3.9±0.9)%, consistent with the standard model prediction.

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