Improved measurement of absolute branching fraction of the inclusive decay Λ_c⁺ → K_S⁰ X

2025/02/28 by BESIII Collaboration, Ablikim, M., Achasov, M. N. +676
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2502.20821

Abstract

By analyzing 4.5 fb^-1 of e⁺e^- collision data accumulated with the BESIII detector at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV, we report the measurement of the absolute branching fraction (BF) of the inclusive decay Λ_c⁺ → K_S⁰ X using the double-tag technique. The result is B(Λ_c⁺ → K_S⁰ X)=(10.9±0.2±0.1)%, where the first uncertainty is statistical and the second is systematic. This result indicates that there are still undiscovered decay channels containing K_S⁰ in the final state with a combined BF of (3.1±0.4)%. The BF of the inclusive decay Λ_c⁺ → K⁰ / K⁰ X is calculated to be B(Λ_c⁺ → K⁰ / K⁰ X)=(21.8 ±0.4 ±0.2 ±1.1)%, where the third uncertainty accounts for a possible difference between B(Λ_c⁺ → K_S⁰ X) and B(Λ_c⁺ → K_L⁰ X). The result is in agreement with the prediction of the statistical isospin model.

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