Evidence for the Singly Cabibbo Suppressed Decay Λ_c⁺ → pη and Search for Λc+ →pπ⁰

We study the singly Cabibbo suppressed decays Λ_c⁺ → pη and Λ_c⁺ → pπ⁰ using Λ_c⁺Λ̅_c⁻ pairs produced by e⁺e⁻ collisions at a center-of-mass energy of √s̅ = 4.6 GeV. The data sample was collected by the BESIII detector at the BEPCII collider and corresponds to an integrated luminosity of 567 pb⁻¹. We find the first evidence for the decay Λ_c⁺ → pη with a statistical significance of 4.2σ and measure its branching fraction to be ℬ(Λ_c⁺ → pη) = (1.24 ± 0.28(stat) ± 0.10(syst)) x 10⁻³. No significant Λ_c⁺ → pπ⁰ signal is observed. We set an upper limit on its branching fraction ℬ(Λ_c⁺ → pπ⁰) < 2.7 x 10⁻⁴ at the 90% confidence level.