Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons and into Photons

Abstract

The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, $Λ_C\rightarrow p{ρ^0}, pω$, $Ξ_C^{+,0}\rightarrowΣ^{+,0}ϕ, Σ^{+,0}{ρ^0}, Σ^{+,0}ω$ and $Ξ_C^{0}\rightarrowΛϕ, Λρ, Λω$. The input from two recent experimental results on $Λ_C$ decays allows the estimation of the branching ratios for these modes, which turn out to be between $10^{-4}$ and $10^{-3}$. The long distance contribution of these transitions via vector meson dominance to the radiative weak processes $Λ_C\rightarrow pγ$, $Ξ_C\rightarrowΣγ$ and $Ξ_C^0\rightarrowΛγ$ leads to quite small branching ratios, $10^{-6}-10^{-9}$; the larger value holds if a sum rule between the coupling constants of the vector mesons is broken.