Observation of mixing-inducedCPviolation in the neutralBmeson system

Kazuo Abe ,T Abe,A Ishikawa,S Schrenk,S L Olsen,Heejong Kim,D Liventsev,J H Kang,S Behari,T Hojo,K S Park,J Dragic,E Nakano,A Gordon,O Nitoh,F Handa,K Suzuki,S Uno,Y Ban,T Nozaki,A Kuzmin,A Drutskoy,Y Teramoto,M Bračko,H Park,H Tajima,H Guler,T Tsuboyama,W Ostrowicz,O Schneider,C S Park,T Iijima,P Pakhlov,J Haba,T Nakadaira,K Trabelsi,E M Heenan,K Senyo,K Neichi,R Kulasiri,T Tomura,A Yamaguchi,H Kawai,T Hara,N Gabyshev,S H Lee,M Yamauchi,F Takasaki,T Tsukamoto,H Kichimi,T Okabe,I Adachi,T Sumiyoshi,G N Taylor,T Nagamine,Y Mikami,Y Yuan,E Won,J Macnaughton,V Eiges,P Chang,C Schwanda,K Inami,T Kawasaki,T Igaki,R Itoh,M Takita,D Žontar,H Miyata,K Ueno,Y Watanabe,I Higuchi,M E Sevior,A Satpathy,Y Sakai,J Tanaka,K Rybicki,T Hokuue,P Križan,T Matsuishi,H Yuta,L E Piilonen,Z Natkaniec,B G Cheon,M Akatsu,S Semenov,G R Moloney,J S Lange,B Shwartz,A M Bakich,K Sumisawa,A Sugi,H Kakuno,S Ogawa,R Chistov,Y Hoshi,T Ohshima,S Korpar,J Yashima,Y Yusa,F Mandl,H Hayashii,L S Peak,S Uehara,N C Hastings,A Sugiyama,P Kapusta,S Eidelman,Y Iwasaki,Y Ushiroda,M Satapathy,A Garmash,T Aushev,S Noguchi,P Krokovny,G Leder,H Ozaki,H Miyake,H Shibuya,B Golob,K Kinoshita,S Okuno,M Nakao,C H Wang,C C Zhang,Y Miyabayashi,F Fang,Y Asano,Y Choi,N Katayama,T Higuchi,S Matsumoto,T E Browder,K Tamai,S Nishida,T Matsumoto,Y Yamashita,S Tokuda,K Miyabayashi,M Yamaga,P K Behera,R S Guo ,Akira Murakami ,Y Chào ,K Hara,Shigeki Mori ,A Bożek ,Y Yamada,H Ishino,H Aihara,Y Zheng,C Fukunaga,C C Wang,S K Choi ,T H Kim,V Zhilich,T Takahashi,Y Kwon ,J B Singh,M Różańska ,H O Kim,K E Varvell,M.-Z Wang,H Ikeda,D Jackson ,G Majumder,T Gershon,D Marlow,Abe R ,Y Nagashima,S Suzuki,M Tomoto,K Hanagaki,Hiroshi Hamasaki ,S.-C Hsu,E Prebys,E Banaś ,H K Jang,W Trischuk,Takashi Mori ,J W Nam,Y Unno,B C.k Casey ,W Mitaroff,H J Kim,Dong Liu ,R.-S Lu,C W Park,F J Ronga ,S K Kim,M Yokoyama,T Aso,H Iwasaki,W.-S Hou,M Tanaka,J Zhang,J P Perroud ,Y Nagasaka,S N Tovey,H Pałka ,J S Kang,Suneel Kumar ,S Hou ,B Yabsley ,Byoung Sup Ahn,Hsuan‐Cheng Huang ,C.w Everton ,Y Kawakami,H Yamamoto,V Sidorov,T Yamanaka,M Hazumi,N Kawamura,D W Kim,N Tamura,Y Enari,S Stanič,S Vahsen ,M Fukushima,H Konishi,M Peters,J G Wang,A Bondar,J L Rodriguez,A Limosani,Hyun Woo Kim ,H Sagawa

doi:10.1103/physrevd.66.032007

Abstract

This article describes an observation of mixing-induced CP violation and a measurement of the CP violation parameter, sin2φ1, with the Belle detector at the KEKB asymmetric e+e− collider. Using a data sample of 29.1 fb−1 recorded on the Υ(4S) resonance that contains 31.3 million BB¯ pairs, we reconstruct decays of neutral B mesons to the following CP eigenstates: J/ψKS0, ψ(2S)KS0, χc1KS0, ηcKS0, J/ψKL0 and J/ψK*0. The flavor of the accompanying B meson is identified by combining information from primary and secondary leptons, K± mesons, Λ baryons, slow and fast pions. The proper-time interval between the two B meson decays is determined from the distance between the two decay vertices measured with a silicon vertex detector. The result sin2φ1=0.99±0.14(stat)±0.06(syst) is obtained by applying a maximum likelihood fit to the 1137 candidate events. We conclude that there is large CP violation in the neutral B meson system. A zero value for sin2φ1 is ruled out by more than six standard deviations.Received 13 February 2002DOI:https://doi.org/10.1103/PhysRevD.66.032007©2002 American Physical Society

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