Measurement of thee+e−→π+π−J/ψCross Section Via Initial-State Radiation at Belle

C Z Yuan,M Tanaka,W T Chen,S E Lee,J B Singh,M E Sevior,V Zhilich,Y Hoshi,T Hokuue,M Danilov,Y Sakai,T E Browder,C H Wang,G Pakhlova,S Uehara,H J Hyun,M Dash,C C Wang,A Sokolov,C C Zhang,S Villa,Z P Zhang,H Park,R Itoh,W.-S Hou,K Kinoshita,A Somov,K Senyo,S Ogawa,A Zupanc,L S Peak,M Starič,Y Miyazaki,H Kichimi,C P Shen,N Katayama,M Hazumi,V Balagura,J Schümann,C C Kuo,A Kuzmin,K Ikado,F Takasaki,Y Iwasaki,I Adachi,H Aihara,I Bedny,J Brodzicka,H Miyata,S L Olsen,J H Kang,P Križan,B Shwartz,Y J Kim,H Miyake,H Shibuya,Y Usov,S Eidelman,H Kawai,U Bitenc,G Varner,P Chang,D Liventsev,D Marlow,D H Kah,Y Teramoto,Y Yamashita,A Yamaguchi,X L Wang,M Shapkin,S Korpar,F Mandl,B Golob,Y.-J Kwon,Y Choi,K Inami,J Haba,N Gabyshev,Y Nagasaka,D Heffernan,V Zhulanov,M Bračko,S Uno,T Ohshima,K Hayasaka,O Schneider,T Iijima,Y Unno,T Medvedeva,V Aulchenko,S Fratina,Y Watanabe,M Nakao,I Tikhomirov,E Won,S Okuno,S Nishida,O Nitoh,Y Liu,R Seidl,T Aushev,K Vervink,H Ozaki,A Bondar,G N Taylor,Z Natkaniec,P Pakhlov,S Bahinipati,H Hayashii,T Lesiak,P Wang,A Matyja,A Ishikawa,K E Varvell,H Ha,T Kawasaki,B G Cheon,S Mconie,A Vinokurova,L E Piilonen,R Mizuk,R Chistov,A Chen,K S Park,W Mitaroff,T Sumiyoshi,J Dalseno,K Miyabayashi,P Krokovny,A Bożek ,Rajeev Kumar ,Takashi Mori ,J G Shiu ,M C Chang ,B Yabsley ,Y Hsiung ,E L Barberio ,S W Lin ,Hiroshi Kaji ,H Pałka ,I S Cho ,K F Chen

doi:10.1103/physrevlett.99.182004

Abstract

The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.

Full Text