From Ξb → Λbπ to Ξc → Λcπ

Using a successful framework for describing S-wave hadronic decays of light hyperons induced by a subprocess s→u(u¯d), we presented recently a model-independent calculation of the amplitude and branching ratio for Ξb−→Λbπ− in agreement with a LHCb measurement. The same quark process contributes to Ξc0→Λcπ−, while a second term from the subprocess cs→cdcs→cd has been related by Voloshin to differences among total decay rates of charmed baryons. We calculate this term and find it to have a magnitude approximately equal to the s→u(u¯d) term. We argue for a negligible relative phase between these two contributions, potentially due to final state interactions. However, we do not know whether they interfere destructively or constructively. For constructive interference one predicts B(Ξc0→Λcπ−)=(1.94±0.70)×10−3 and B(Ξc+→Λcπ0)=(3.86±1.35)×10−3. For destructive interference, the respective branching fractions are expected to be less than about 10−410−4 and 2×10−42×10−4.