Evidence for the semileptonic decays Λ_c⁺ → Σ^± π^∓ e⁺ ν_e

2025/12/04 by BESIII Collaboration, Ablikim, M., Achasov, M. N. +680
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2512.05178

Abstract

Using 4.5 fb^-1 of e⁺e^- collision data collected by the BESIII detector at center-of-mass energies between 4.600 and 4.699 GeV, we search for the semileptonic decays Λ_c⁺ → Σ⁺ π^- e⁺ ν_e and Λ_c⁺ → Σ^- π⁺ e⁺ ν_e for the first time. Assuming their branching fractions are equal under isospin symmetry, evidence for Λ_c⁺ → Σ^± π^∓ e⁺ ν_e is reported with a significance of 3.6σ. The corresponding branching fraction is measured to be B(Λ_c⁺ → Σ^±π^∓ e⁺ν_e) = (7.7^+2.5_-2.3_{\rm stat.}±1.3_{\rm syst.})× 10^-4, which is consistent with quark model predictions within two standard deviations.

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