Pursuit of new physics within the $\Lambda_c\to \Delta K$ decays

TL;DR

This paper discusses how measuring CP asymmetry in certain Lambda_c+ decays can reveal potential new physics beyond the Standard Model, emphasizing the importance of future experimental branching fraction data.

Contribution

It proposes a method to determine CP asymmetry in Lambda_c+ decays that avoids theoretical ambiguities and can test for new physics effects.

Findings

CP asymmetry depends on specific decay branching fractions

The approach avoids loop-induced and SU(3)_F breaking uncertainties

Future measurements are crucial for reducing uncertainties

Abstract

We point out the $CP$ asymmetry in the chain decay of $\Lambda_c^+\to \Delta^+K(t)(\to \pi^+\pi^-)$ is determined by the branching fractions of $\Lambda^+_c\to \Delta^{++} K^-$, $\Lambda^+_c\to \Delta^{+} K^0_{S,L}$ and $\Lambda^+_c\to \Delta^{0} K^+$ 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 $\Lambda_c^+$ decays into $\Delta^+$ 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.