Journal article
Observation of a near-threshold enhancement in the e e- →Λc Λc- Cross section using initial-state radiation
G Pakhlova, I Adachi, H Aihara, K Arinstein, V Aulchenko, T Aushev, AM Bakich, V Balagura, I Bedny, V Bhardwaj, U Bitenc, A Bondar, A Bozek, M Bračko, J Brodzicka, TE Browder, P Chang, A Chen, BG Cheon, CC Chiang Show all
Physical Review Letters | AMER PHYSICAL SOC | Published : 2008
Abstract
We report a measurement of the exclusive e+e-→Λc+Λc- cross section as a function of center-of-mass energy near the Λc+Λc- threshold. A clear peak with a significance of 8.2σ is observed in the Λc+Λc- invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of M=[4634-7+8(stat)-8+5(syst)]MeV/c2 and Γtot=[92- 24+40(stat)-21+10(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 Υ(4S) resonance and nearby continuum with an integrated luminosity of 695fb-1 at the KEKB asymmetric-energy e+e- collider. © 2008 The A..
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Funding Acknowledgements
We thank the KEKB group for excellent operation of the accelerator, the KEK cryogenics group for efficient solenoid operations, and the KEK computer group and the NII for valuable computing and SINET3 network support. We acknowledge support from MEXTand JSPS (Japan); ARC and DEST (Australia); NSFC (China); DST (India); MOEHRD, KOSEF and KRF (Korea); KBN (Poland); MES and RFAAE (Russia); ARRS (Slovenia); SNSF (Switzerland); NSC and MOE (Taiwan); and DOE (USA).