Weak Decays of Doubly Heavy Baryons: ${\cal B}_{cc}\to {\cal B} D^{(*)}$

TL;DR

This paper calculates the weak decay rates of doubly charmed baryons into light baryons and D^{(*)} mesons, highlighting the significance of polarization states and the bow-tie decay mechanism, with predictions for branching ratios.

Contribution

It provides the first detailed calculation of ${ m B}_{cc} o { m B} D^{(*)}$ decay branching ratios including both short and long distance effects, emphasizing the role of polarization and decay mechanisms.

Findings

${ m BR}(\Xi_{cc}^{++} ightarrow ext{Sigma}^{+}D^{*+})$ estimated between 0.46% and 3.33%.

${ m BR}(\Xi_{cc}^{+} ightarrow ext{Lambda}D^{*+})$ estimated between 0.38% and 2.63%.

The bow-tie decay mechanism significantly influences charm decay widths.

Abstract

The discovery of $\Xi_{cc}^{++}$ has inspired new interest in studying doubly heavy baryons. In this study, the weak decays of a doubly charmed baryon ${\cal B}_{cc}$ to a light baryon ${\cal B}$ and a charm meson $D^{(*)}$ (either a pseudoscalar or a vector one) are calculated. Following our previous work, we calculate the short distance contributions under the factorization hypothesis, whereas the long distance contributions are modeled as the final state interactions which are calculated with the one particle exchange model. We find that the ${\cal B}_{cc}\to {\cal B} D^{*}$ decays' branching ratios are obviously larger, as they receive contributions of more polarization states. Among the decays that we investigate, the following have the largest branching fractions: ${\cal BR}(\Xi_{cc}^{++}\rightarrow\Sigma^{+}D^{*+}) \in [0.46\%, 3.33\%]$ estimated with $\tau_{\Xi_{cc}^{++}}=256$ fs; ${\cal BR}(\Xi_{cc}^{+}\rightarrow\Lambda D^{*+}) \in [0.38\%, 2.63\%]$ and ${\cal BR}(\Xi_{cc}^{+}\rightarrow\Sigma^{0} D^{*+}) \in [0.45\%, 3.16\%]$ with $\tau_{\Xi_{cc}^+}=45$ fs; and ${\cal BR}(\Omega_{cc}^{+}\rightarrow\Xi^{0} D^{*+}) \in [0.27\%, 1.03\%]$, ${\cal BR}(\Omega_{cc}^{+}\rightarrow\Xi^{0} D^{+}) \in [0.07\%, 0.44\%]$ and ${\cal BR}(\Omega_{cc}^{+}\rightarrow\Sigma^{0} D^{*+}) \in [0.06\%, 0.45\%]$ with $\tau_{\Omega_{cc}^+}=75$ fs. By comparing the decay widths of pure color commensurate channels with those of pure bow-tie ones, we find that the bow-tie mechanism plays an important role in charm decays.