2025/10/23 by Belle, Collaborations, Belle II, : +321
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)
paper · doi:10.48550/arxiv.2510.20882
Using data samples of 988.4 fb-1 and 427.9 fb-1 collected with the Belle and Belle II detectors, we present a study of the singly Cabibbo-suppressed decays Ξc0 → Λη, Λη', and Λπ0. We observe the decay Ξc0 → Λη and find evidence for the decay Ξc0 → Λη', with corresponding branching ratios determined to be B(Ξc0 → Λη)/B(Ξc0 → Ξ- π+)= (4.16 ± 0.91 ± 0.23)% and B(Ξc0 → Λη')/B(Ξc0 → Ξ- π+)= (2.48 ± 0.82 ± 0.12)%, respectively. We find no significant signal in the Ξc0 → Λπ0 decay mode and set an upper limit at the 90% credibility level of B(Ξc0 → Λπ0)/B(Ξc0 → Ξ- π+)< 3.5%. Multiplying these ratios by the world-average branching fraction of the normalization channel, B(Ξc0 → Ξ- π+)=(1.43 ± 0.27)%, we obtain the absolute branching fractions of B(Ξc0 → Λη)= (5.95 ± 1.30 ± 0.32 ± 1.13) × 10-4, B(Ξc0 → Λη')= (3.55 ± 1.17 ± 0.17 ± 0.68) × 10-4, and an upper limit at the 90% credibility level on the absolute branching fraction of B(Ξc0 → Λπ0)< 5.2 × 10-4. The quoted first and second uncertainties are statistical and systematic, respectively, while the third uncertainties arise from the branching fraction of the normalization mode. These results are consistent with most theoretical predictions and further the understanding of the underlying decay mechanisms.