Observation of the Decay Λ_c⁺→ Σ⁻π⁺π⁺π⁰
We report the first observation of the decay Λ_c⁺→ Σ⁻π⁺π⁺π⁰, based on data obtained in e⁺e⁻ annihilations with an integrated luminosity of 567 pb⁻¹ at √s̅=4.6 GeV. The data were collected with the BESIII detector at the BEPCII storage rings. The absolute branching fraction B(Λ_c⁺ → Σ⁻π⁺π⁺π⁰ is determined to be (2.11 ± 0.33(stat.) ± 0.14(syst.))%. In addition, an improved measurement of B( Λ_c⁺→ Σ⁻π⁺π⁺) is determined as (1.81 ± 0.17(stat.) ± 0.09(syst.))%.