From $\Xi_b \to \Lambda_b \pi$ to $\Xi_c \to \Lambda_c \pi$

TL;DR

This paper extends a successful model for hyperon decays to charmed baryons, calculating decay amplitudes and branching ratios, and discusses interference effects affecting these predictions.

Contribution

It provides a model-independent calculation of charmed baryon decay amplitudes, including a new estimate of the second subprocess contribution and interference effects.

Findings

Calculated branching ratios for $\Xi_c^0 o \Lambda_c \pi^-$ and $\Xi_c^+ o \Lambda_c \pi^0$ under different interference scenarios.

Found the second subprocess contribution to be comparable in magnitude to the primary process.

Predicted branching ratios vary significantly depending on interference, with potential values around 10^{-3} or less than 10^{-4}.

Abstract

Using a successful framework for describing S-wave hadronic decays of light hyperons induced by a subprocess $s \to u (\bar u d)$, we presented recently a model-independent calculation of the amplitude and branching ratio for $\Xi^-_b \to \Lambda_b \pi^-$ in agreement with a LHCb measurement. The same quark process contributes to $\Xi^0_c \to \Lambda_c \pi^-$, while a second term from the subprocess $cs \to cd$ 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 $s \to u (\bar u d)$ 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 ${\cal B}(\Xi_c^0 \to \Lambda_c \pi^-) = (1.94 \pm 0.70)\times 10^{-3}$ and ${\cal B}(\Xi_c^+ \to \Lambda_c \pi^0) = (3.86 \pm 1.35)\times 10^{-3}$. For destructive interference, the respective branching fractions are expected to be less than about $10^{-4}$ and $2 \times 10^{-4}$.