Measurement of Singly Cabibbo Suppressed Decays Λc+→p π+π- and Λc+→p K+K-

Using 567 pb^-1 of data collected with the BESIII detector at a center-of-mass energy of √{s }=4.599 GeV , near the Λ_c⁺Λ_¯c^- threshold, we study the singly Cabibbo-suppressed decays Λ_c⁺→p π⁺π^- and Λ_c⁺→p K⁺K^- . By normalizing with respect to the Cabibbo-favored decay Λ_c⁺→p K^-π⁺ , we obtain ratios of branching fractions: [B (Λ_c⁺→p π⁺π^-)/B (Λ_c⁺→p K^-π⁺)]=(6.70 ±0.48 ±0.25 )% , [B (Λ_c⁺→p ϕ )/B (Λ_c⁺→p K^-π⁺)]=(1.81 ±0.33 ±0.13 )% , and [B (Λ_c⁺→p K⁺K_non^{-ϕ -})/B (Λ_c⁺→p K^-π⁺)]=(9.36 ±2.22 ±0.71 )×10^-3 , where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay Λ_c⁺→p π⁺π^- is observed for the first time, and the precision of the branching fraction for Λ_c⁺→p K⁺K_non^{-ϕ -} and Λ_c⁺→p ϕ is significantly improved.