Measurements of branching fractions of Ac plus , E plus eta and Ac plus , E plus eta i and asymmetry parameters of Ac+, E+pi 0, Ac+, E+ eta, and Ac plus , E plus eta i


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American Physical Society


We report a study of Λc+→ς+π0, Λc+→ς+η, and Λc+→ς+η′ using the data sample corresponding to an integrated luminosity of 980 fb-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fractions relative to Λc+→ς+π0 are measured as BΛc+→ς+η/BΛc+→ς+π0=0.25±0.03±0.01 and BΛc+→ς+η′/BΛc+→ς+π0=0.33±0.06±0.02. Using BΛc+→ς+π0=(1.25±0.10)%, we obtain BΛc+→ς+η=(3.14±0.35±0.17±0.25)×10-3 and BΛc+→ς+η′=(4.16±0.75±0.25±0.33)×10-3. Here the uncertainties are statistical, systematic, and from BΛc+→ς+π0, respectively. The ratio of the branching fraction of Λc+→ς+η′ with respect to that of Λc+→ς+η is measured to be BΛc+→ς+η′/BΛc+→ς+η=1.34±0.28±0.08. We update the asymmetry parameter of Λc+→ς+π0, ας+π0=-0.48±0.02±0.02, with a considerably improved precision. The asymmetry parameters of Λc+→ς+η and Λc+→ς+η′ are measured to be ας+η=-0.99±0.03±0.05 and ας+η′=-0.46±0.06±0.03 for the first time.