Observation of a near-threshold enhancement in the e+e- -->Lambda+_(c)Lambda-_(c) cross section using initial-state radiation

G Pakhlova; I Adachi; H Aihara; K Arinstein; V Aulchenko; T Aushev; A M Bakich; V Balagura; I Bedny; V Bhardwaj; U Bitenc; A Bondar; A Bozek; M Bracko; J Brodzicka; T E Browder; P Chang; A Chen; B G Cheon; C-C Chiang; R Chistov; I-S Cho; S-K Choi; Y Choi; J Dalseno; M Danilov; M Dash; S Eidelman; N Gabyshev; H Ha; J Haba; K Hayasaka; M Hazumi; D Heffernan; Y Hoshi; W-S Hou; Y B Hsiung; H J Hyun; T Iijima; K Inami; A Ishikawa; H Ishino; R Itoh; M Iwasaki; Y Iwasaki; D H Kah; J H Kang; N Katayama; H Kawai; T Kawasaki; H Kichimi; H J Kim; H O Kim; S K Kim; Y I Kim; Y J Kim; K Kinoshita; P Krizan; P Krokovny; R Kumar; A Kuzmin; Y-J Kwon; S-H Kyeong; J S Lange; J S Lee; S E Lee; T Lesiak; J Li; A Limosani; C Liu; D Liventsev; F Mandl; A Matyja; K Miyabayashi; H Miyata; Y Miyazaki; R Mizuk; T Mori; E Nakano; M Nakao; Z Natkaniec; S Nishida; O Nitoh; S Noguchi; S Ogawa; T Ohshima; S Okuno; S L Olsen; H Ozaki; P Pakhlov; H Palka; C W Park; H Park; H K Park; L S Peak; L E Piilonen; A Poluektov; H Sahoo; Y Sakai; O Schneider; K Senyo; M Shapkin; C P Shen; J-G Shiu; B Shwartz; J B Singh; A Sokolov; S Stanic; M Staric; T Sumiyoshi; M Tanaka; G N Taylor; Y Teramoto; I Tikhomirov; S Uehara; T Uglov; Y Unno; S Uno; P Urquijo; Y Usov; G Varner; C H Wang; M-Z Wang; P Wang; X L Wang; Y Watanabe; R Wedd; E Won; B D Yabsley; Y Yamashita; M Yamauchi; C Z Yuan; C C Zhang; Z P Zhang; V Zhilich; V Zhulanov; T Zivko; A Zupanc; O Zyukova; Belle Collaboration

doi:10.1103/PhysRevLett.101.172001

Observation of a near-threshold enhancement in the e+e- -->Lambda+_(c)Lambda-_(c) cross section using initial-state radiation

Phys Rev Lett. 2008 Oct 24;101(17):172001. doi: 10.1103/PhysRevLett.101.172001. Epub 2008 Oct 24.

Authors

G Pakhlova¹, I Adachi, H Aihara, K Arinstein, V Aulchenko, T Aushev, A M Bakich, V Balagura, I Bedny, V Bhardwaj, U Bitenc, A Bondar, A Bozek, M Bracko, J Brodzicka, T E Browder, P Chang, A Chen, B G Cheon, C-C Chiang, R Chistov, I-S Cho, S-K Choi, Y Choi, J Dalseno, M Danilov, M Dash, S Eidelman, N Gabyshev, H Ha, J Haba, K Hayasaka, M Hazumi, D Heffernan, Y Hoshi, W-S Hou, Y B Hsiung, H J Hyun, T Iijima, K Inami, A Ishikawa, H Ishino, R Itoh, M Iwasaki, Y Iwasaki, D H Kah, J H Kang, N Katayama, H Kawai, T Kawasaki, H Kichimi, H J Kim, H O Kim, S K Kim, Y I Kim, Y J Kim, K Kinoshita, P Krizan, P Krokovny, R Kumar, A Kuzmin, Y-J Kwon, S-H Kyeong, J S Lange, J S Lee, S E Lee, T Lesiak, J Li, A Limosani, C Liu, D Liventsev, F Mandl, A Matyja, K Miyabayashi, H Miyata, Y Miyazaki, R Mizuk, T Mori, E Nakano, M Nakao, Z Natkaniec, S Nishida, O Nitoh, S Noguchi, S Ogawa, T Ohshima, S Okuno, S L Olsen, H Ozaki, P Pakhlov, H Palka, C W Park, H Park, H K Park, L S Peak, L E Piilonen, A Poluektov, H Sahoo, Y Sakai, O Schneider, K Senyo, M Shapkin, C P Shen, J-G Shiu, B Shwartz, J B Singh, A Sokolov, S Stanic, M Staric, T Sumiyoshi, M Tanaka, G N Taylor, Y Teramoto, I Tikhomirov, S Uehara, T Uglov, Y Unno, S Uno, P Urquijo, Y Usov, G Varner, C H Wang, M-Z Wang, P Wang, X L Wang, Y Watanabe, R Wedd, E Won, B D Yabsley, Y Yamashita, M Yamauchi, C Z Yuan, C C Zhang, Z P Zhang, V Zhilich, V Zhulanov, T Zivko, A Zupanc, O Zyukova; Belle Collaboration

Affiliation

¹ Institute for Theoretical and Experimental Physics, Moscow.

PMID: 18999743
DOI: 10.1103/PhysRevLett.101.172001

Abstract

We report a measurement of the exclusive e+ e- -->Lambda+_(c)Lambda-_(c) cross section as a function of center-of-mass energy near the Lambda+_(c)Lambda-_(c) threshold. A clear peak with a significance of 8.2sigma is observed in the Lambda+_(c)Lambda-_(c) invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of M=[4634 (+8)_(-7)(stat)(+5)_(-8)(syst)] MeV/c(2) and Gamma_(tot)=[92 (+40)_(-24)(stat)(+10)_(-21)(syst)] MeV are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the Upsilon(4S) resonance and nearby continuum with an integrated luminosity of 695 fb(-1) at the KEKB asymmetric-energy e+ e- collider.