Measurement of branching fractions of Λc+ →p KS0 KS0 and Λc+ →p KS0 η at Belle
We present a study of a singly Cabibbo-suppressed decay Λc+→pKS0KS0 and a Cabibbo-favored decay Λc+→pKS0η based on 980 fb-1 of data collected by the Belle detector, operating at the KEKB energy-asymmetric e+e- collider. We measure their branching fractions relative to Λc+→pKS0: B(Λc+→pKS0KS0)/B(Λc+→pKS0)=(1.48±0.08±0.04)×10-2 and B(Λc+→pKS0η)/B(Λc+→pKS0)=(2.73±0.06±0.13)×10-1. Combining with the world average B(Λc+→pKS0), we have the absolute branching fractions, B(Λc+→pKS0KS0)=(2.35±0.12±0.07±0.12)×10-4 and B(Λc+→pKS0η)=(4.35±0.10±0.20±0.22)×10-3. The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the uncertainty on B(Λc+→pKS0). The mode Λc+→pKS0KS0 is observed for the first time and has a statistical significance of >10σ. The branching fraction of Λc+→pKS0η has been measured with a threefold improvement in precision over previous results and is found to be consistent with the world average.
