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.



Electroweak interactions, Particles (Nuclear physics)--Decay, Baryons--Charm, Electron-positron interactions


National Key Basic Research Program of China (no. 2015CB856700); National Natural Science Foundation of China (NSFC) (nos. 11125525, 11235011, 11322544, 11335008, 11425524, 11625523, 11635010, 11375170, 11275189, 11475164, 11475169, 11605196, 11605198); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (nos. U1232201, U1332201, U1532257, U1532258, U1532102); CAS (nos.KJCX2-YW-N29, No. KJCX2-YWN45, QYZDJ-SSW-SLH003); Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) (no. 530-4CDP03); Ministry of Development of Turkey (no. DPT2006K-120470); U.S. Department of Energy (nos. DE-FG02-05ER41374, DE-SC-0010504, DE-SC-0010118, DE-SC-0012069); WCU Program of National Research Foundation of Korea (no. R32-2008-000-10155-0).


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