Measurements of the branching fractions B ( B − → ¯ Λ − c Ξ ' 0 c ) , B ( B − → ¯ Λ − c Ξ c ( 2645 ) 0 ) and B ( B − → ¯ Λ − c Ξ c ( 2790 ) 0 )

Abstract

Using the data sample of 711

fb − 1 of Υ ( 4 S ) on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays B − → ¯ Λ − c Ξ ' 0 c , B − → ¯ Λ − c Ξ c ( 2645 ) 0 , and B − → ¯ Λ − c Ξ c ( 2790 ) 0 . The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against ¯ Λ − c baryons in selected B − candidates. The branching fraction of B − → ¯ Λ − c Ξ c ( 2790 ) 0 is measured to be ( 1.1 ± 0.4 ± 0.2 ) × 10 − 3 , where the first uncertainty is statistical and the second is systematic. The 90% credibility level upper limits on B ( B − → ¯ Λ − c Ξ ' 0 c ) and B ( B − → ¯ Λ − c Ξ c ( 2645 ) 0 ) are determined to be 6.5 × 10 − 4 and 7.9 × 10 − 4 , respectively.