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Observation of a Near-Threshold Enhancement in the e{sup +}e{sup -}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -} Cross Section Using Initial-State Radiation

Journal Article · · Physical Review Letters
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  1. Institute for Theoretical and Experimental Physics, Moscow (Russian Federation)
  2. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
We report a measurement of the exclusive e{sup +}e{sup -}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -} cross section as a function of center-of-mass energy near the {lambda}{sub c}{sup +}{lambda}{sub c}{sup -} threshold. A clear peak with a significance of 8.2{sigma} is observed in the {lambda}{sub c}{sup +}{lambda}{sub c}{sup -} invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of M=[4634{sub -7}{sup +8}(stat){sub -8}{sup +5}(syst)] MeV/c{sup 2} and {gamma}{sub tot}=[92{sub -24}{sup +40}(stat){sub -21}{sup +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 {upsilon}(4S) resonance and nearby continuum with an integrated luminosity of 695 fb{sup -1} at the KEKB asymmetric-energy e{sup +}e{sup -} collider.
OSTI ID:
21179842
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 17 Vol. 101; ISSN 0031-9007; ISSN PRLTAO
Country of Publication:
United States
Language:
English