|Title:||Observation of Ξ <inf>c</inf>(2930) <sup>0</sup> and updated measurement of <sup>B-</sup>→<sup>K-</sup>Λc+Λ¯c- at Belle: Belle Collaboration||Authors:||Iwasaki, Y.
Kim, K. T.
Hedges, M. T.
Joo, K. K.
Lee, S. C.
|Issue Date:||1-Mar-2018||Journal Volume:||78||Journal Issue:||3||Source:||European Physical Journal C||Abstract:||
© 2018, The Author(s). We report the first observation of the Ξ c(2930) 0 charmed-strange baryon with a significance greater than 5σ. The Ξ c(2930) 0 is found in its decay to K-Λc+ in B-→K-Λc+Λ¯c- decays. The measured mass and width are [2928.9±3.0(stat.)-12.0+0.9(syst.)] MeV/c2 and [19.5±8.4(stat.)-7.9+5.9(syst.)] MeV, respectively, and the product branching fraction is B(B-→Ξc(2930)0Λ¯c-)B(Ξc(2930)0→K-Λc+)=[1.73±0.45(stat.)±0.21(syst.)]×10-4. We also measure B(B-→K-Λc+Λ¯c-)=[4.80±0.43(stat.)±0.60(syst.)]×10-4 with improved precision, and search for the charmonium-like state Y(4660) and its spin partner, Yη, in the Λc+Λ¯c- invariant mass spectrum. No clear signals of the Y(4660) nor its spin partner are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of (772 ± 11) × 10 6BB¯ pairs collected at the Υ (4 S) resonance by the Belle detector at the KEKB asymmetric energy electron–positron collider.
|Appears in Collections:||物理學系|
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