Pursuit of new physics within the $Λ_c\to ΔK$ decays

Abstract

We point out the $CP$ asymmetry in the chain decay of $Λ_c^+\to Δ^+K(t)(\to π^+π^-)$ is determined by the branching fractions of $Λ^+_c\to Δ^{++} K^-$, $Λ^+_c\to Δ^{+} K^0_{S,L}$ and $Λ^+_c\to Δ^{0} K^+$ modes under the isospin symmetry. The ambiguities from loop-induced quantities and $SU(3)_F$ breaking hadronic effects are avoided. Once the $CP$ asymmetry in the $Λ_c^+$ decays into $Δ^+$ and neutral kaons is confirmed by experiments, we can check if it is beyond the Standard Model, or verify the $CP$-violating effect resulted from the interference between the Cabibbo-favored and the doubly Cabibbo-suppressed amplitudes with the neutral kaon mixing. Future measurements of branching fractions play a critical role in reducing the uncertainties.