Observation of B^{0}→pΛ[over ¯]D^{(*)-}.

Y Y Chang ,K Tanida,H Farhat,A Kuzmin,T Iijima,A Ishikawa,Y Li,O Grzymkowska,D Dutta,Y Watanabe,H Hayashii,P Krokovny,J Dingfelder,I Badhrees,R Pestotnik,M Masuda,C Schwanda,M Sumihama,N Gabyshev,K Sumisawa,Y Iwasaki,J Libby,A Abdesselam,V Savinov,K Miyabayashi,A Zupanc,A Rostomyan,R Gillard,A Chen,K Inami,Y Sakai,M.-Z Wang,E Nakano,Z Doležal,Y Choi,M Bračko,Y.-T Lai,P Vanhoefer,V Gaur,T Kawasaki,V Zhilich,M Petrič,J Rauch,S Yashchenko,J Dalseno,A Moll,S Korpar,H Ozaki,H Aihara,W.-S Hou,M Starič,S Ganguly,V Chobanova,R Mizuk,L Li,D Červenkov,T Sanuki,D Cinabro,H Sahoo,S Uno,D Joffe,K Adamczyk,P Pakhlov,S Al Said,D Liventsev,R Glattauer,T Ferber,O Schneider,J Yelton,T Aushev,Y Yusa,S Nishida,M Watanabe,S Mohanty,Y Usov,T Kumita,A Bobrov,I Adachi,A Garmash,H Miyata,B Bhuyan,J Haba,G Schnell,J Yamaoka,V Shebalin,C.-L Hsu,P Wang,J Stypula,P Goldenzweig,S Ogawa,G Pakhlova,D Greenwald,C Van Hulse,P Križan,Y Teramoto,V Babu,K Kinoshita,V Zhulanov,V Vorobyev,E Ribežl,T Kuhr,Z Drásal,S Sandilya,Y Unno,F Simon,K Chilikin,S Eidelman,V Chekelian,E Won,G Varner,T Uglov,K Hayasaka,Y Seino,U Tamponi,Y.-J Kwon,P Lukin,A Vossen,M Nakao,S Ryu,T Nanut,M Danilov,H Miyake,M Nayak,T Sumiyoshi,M Ritter,H Atmacan,R Itoh,K Senyo,R Chistov,E Barberio,D Matvienko,Y J Kim ,H K Moon ,L Šantelj ,J G Shiu ,L E Piilonen ,M N Wagner ,I Jaeglé ,B G Fulsom ,I S Seong ,T A Shibata ,J E Fast ,K T Kim ,G B Mohanty ,A M Bakich ,C H Wang ,C W Park ,Y S Sohn ,Y M Goh ,T K Pedlar ,H J Kim ,T E Browder ,D M Asner ,K M Williams ,K K Joo ,Z P Zhang ,C P Shen ,X He ,M E Sevior ,Jyoti Prakash Biswal ,I S Lee ,M J Kim ,B K Pal ,S Choi ,A Bożek ,J B Kim ,Takashi Mori ,S H Kim ,W W Jacobs ,J H Kim ,D Y Kim ,B G Cheon

doi:10.1103/physrevlett.115.221803

Abstract

We report the first observation of the decays B^{0}→pΛ[over ¯]D^{(*)-}. The data sample of 711 fb^{-1} used in this analysis corresponds to 772×10^{6} BB[over ¯] pairs, collected at the ϒ(4S) resonance by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We observe 19.8σ and 10.8σ excesses of events for the two decay modes and measure the branching fractions of B^{0}→pΛ[over ¯]D^{-} and B^{0}→pΛ[over ¯]D^{*-} to be (25.1±2.6±3.5)×10^{-6} and (33.6±6.3±4.4)×10^{-6}, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon (pΛ[over ¯]) system is observed, consistent with that observed in similar B decays.

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