Two-body charmed anti-charmed baryonic $B$ decays

TL;DR

This paper analyzes two-body charmed anti-charmed baryonic B decays using a topological amplitude approach, modeling SU(3) breaking effects, and provides predictions for various decay rates based on existing data.

Contribution

It offers a comprehensive topological amplitude analysis of charmed baryonic B decays, including SU(3) breaking effects and decay rate predictions, expanding understanding of these processes.

Findings

Exchange diagrams are sizable in certain decays.

Large cancellations occur between internal W-tree and exchange W-tree amplitudes.

Predicted decay rates have large uncertainties due to SU(3) breaking effects.

Abstract

We study the rates of two-body charmed anti-charmed baryonic $\overline B\to {\bf B}_c \overline {\bf B}_c$ decays using the topological amplitude approach. All amplitudes of $\overline B\to {\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf { 3_f})$, ${\bf B}_c(\bf 6_f) \overline {\bf B}_c(\bf { 3_f})$, ${\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf {\bar 6_f})$ and ${\bf B}_c(\bf 6_f) \overline {\bf B}_c(\bf {\bar 6_f})$ decays are decomposed topologically. SU(3) breaking effects on these amplitudes, depending on the position of the $s$-quark line, are modeled. Using existing data as inputs, we obtained the following results. (i) In the low-lying $\overline B\to {\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf { 3_f})$ decays, we find that the exchange diagram is sizable. Furthermore, there is a large cancellation between internal $W$-tree and exchange $W$-tree amplitudes. The SU(3) breaking is sizable, 35% SU(3) breaking effects are needed, and they work differently in different amplitudes. The rates of $\overline B\to {\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf { 3_f})$ decays with some excited ${\bf B}_c(\bf {\bar 3_f})$ are also studied. (ii) The $\overline B\to {\bf B}_c(\bf 6_f) \overline {\bf B}_c(\bf { 3_f})$ decays, with low-lying $ \overline {\bf B}_c(\bf { 3_f})$ and low-lying and some excited ${\bf B}_c(\bf 6_f)$ baryons are studied with some predictions on rates obtained. (iii) The $\overline B\to {\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf {\bar 6_f})$ decays with low-lying charmed anti-charmed baryons are studied with some predictions on rates obtained. (iv) Uncertainties in most predicted rates are large, reflecting our current poor understanding of the related SU(3) breaking effects. Measuring these rates can provide very useful information about these effects.