Revisit the diquark of $Λ_c$ in the $Λ_c\to ΛK^+$ and $Λ_c\to Σ^0 K^+$ processes

The spatial distributions of $[ud]$ diquark and heavy-light diquark of the SU(3)-flavor antitriplet charmed baryons are investigated by the two singly Cabibbo-suppressed hadronic weak decays, $Λ_c\to ΛK^+$ and $Λ_c\to Σ^0 K^+$ within the nonrelativistic constituent quark model. The above two spatial distributions are reflected by the two parameters $α_ρ$ and $α_λ$, which are the harmonic oscillator strength parameters of the charmed baryons. These two parameters obtain strong constraints from the decay widths of $Λ_c\to ΛK^+$ and $Λ_c\to Σ^0 K^+$. The larger the harmonic oscillator parameter is, the more compact the spatial distribution will become. The current $α_ρ$ and $α_λ$ indicate that neither the light diquark nor the heavy-light diquark turns out to favor a compact structure. In addition, some selection rules, including the ``$Λ$ selection rule'', can be useful for the search of excited baryons in the heavy-flavor baryon hadronic weak decays.