Observation of the decay Λc+→Σ-π+π+π0

Here, we report the first observation of the decay Λ$\frac{+}{c}$ → Σ ^-π ⁺π ⁺π ⁰, based on data obtained in e ⁺e ^- annihilations with an integrated luminosity of 567 pb ^-1 at $\sqrt{s}$ = 4.6 GeV. The data were collected with the BESIII detector at the BEPCII storage rings. The absolute branching fraction B(Λ$\frac{+}{c}$ → Σ ^-π ⁺π ⁺π ⁰) is determined to be (2.11 ± 0.33(stat.) ± 0.14(syst.))%. In addition, an improved measurement of B(Λ$\frac{+}{c}$ → Σ ^-π ⁺π ⁺π ⁰) is determined as (1.81 ±0.17(stat.) ±0.09(syst.))%.