AI 中文总结
本文重新审视双体粲-反粲重子B衰变，纳入b→uūq贡献并更新拓扑振幅分解，发现该贡献在ΔS=0跃迁中显著增强，可大幅提高某些衰变道速率，对实验验证有重要意义。
AI 中文摘要
我们重新审视了利用拓扑振幅方法研究双体粲-反粲重子 $\overline B\to {\bf B}_c \overline {\bf B}_c$ 衰变的工作。除了 $b\to c\bar c q$ 贡献外，我们还纳入了 $b\to u\bar u q$ 贡献。相应地更新了 $\overline B\to {\bf B}_c({\bf \bar 3_f}) \overline {\bf B}_c({\bf 3_f})$、${\bf B}_c({\bf 6_f}) \overline {\bf B}_c({\bf 3_f})$、${\bf B}_c({\bf \bar 3_f}) \overline {\bf B}_c({\bf \bar 6_f})$ 和 ${\bf B}_c({\bf 6_f}) \overline {\bf B}_c({\bf \bar 6_f})$ 衰变振幅的拓扑分解。尽管在 $\Delta S=-1$ 跃迁中 $b\to u\bar u q$ 贡献受 CKM 压低，但在 $\Delta S=0$ 跃迁中其效应显著放大，因为在 $\Delta S=0$ 跃迁中 $b\to u\bar u q$ 与 $b\to c\bar c q$ 贡献的 CKM 因子相对大小相比 $\Delta S=-1$ 跃迁中的增大了 $\lambda^{-2}$，约为 20 倍。目前 $\overline B\to {\bf B}_c({\bf \bar 3_f}) \overline {\bf B}_c({\bf 3_f})$ 衰变速率的实验数据允许甚至略微偏好非可忽略的 $b\to u\bar u q$ 贡献。这些 $b\to u\bar u q$ 贡献可以使得 $B^-\to \Xi_c^0 \bar \Xi_c^{-}$、$\overline B{}_s^0\to \Lambda_c^+ \bar \Xi_c^{-}$ 和 $\overline B{}^0\to \Xi_c^+ \bar \Xi_c^{-}$ 衰变的速率远大于仅含 $b\to c\bar c d$ 贡献时的结果。测量这些衰变对于阐明 $b\to u\bar u q$ 贡献在双体粲-反粲重子 $\overline B\to {\bf B}_c \overline {\bf B}_c$ 衰变中的作用将是有趣且有用的。
英文摘要
The study of two-body charmed anti-charmed baryonic $\overline B\to {\bf B}_c \overline {\bf B}_c$ decays using the topological amplitude approach is revisited. We include the $b\to u\bar u q$ contributions, in addition to the $b\to c\bar c q$ contributions, to these decays. The topological decomposition 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 ${\bf B}_c(\bf 6_f) \overline {\bf B}_c(\bf {\bar 6_f})$ decay amplitudes are updated accordingly. Although the $b\to u\bar u q$ contributions are Cabibbo-Kobayashi-Maskawa (CKM) suppressed in $ΔS=-1$ transitions, their effects are significantly amplified in $ΔS=0$ transitions, as the relative size of the CKM factors in $b\to u\bar u q$ and $b\to c\bar c q$ contributions in $ΔS=0$ transitions is enlarged by $λ^{-2}$, roughly a factor of 20, from the one in $ΔS=-1$ transitions. Present data in $\overline B\to {\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf { 3_f})$ decay rates allow or even slightly prefer non-negligible $b\to u\bar u q$ contributions. These $b\to u\bar u q$ contributions can allow much larger rates for $B^-\to Ξ_c^0 \bar Ξ_c^{-}$, $\overline B{}_s^0\to Λ_c^+ \bar Ξ_c^{-}$ and $\overline B{}^0\to Ξ_c^+ \bar Ξ_c^{-}$ decays than those only have $b\to c\bar c d$ contributions. Several modes containing only $b\to u\bar u q$ contributions in $\overline B\to {\bf B}_c(\bf 6_f) \overline {\bf B}_c(\bf { 3_f})$, ${\bf B}_c(\bf {\bar 3_f}) \overline {\bf B}_c(\bf {\bar 6_f})$ decays are also identified. Measuring these decays will be interesting and useful in clarifying the role of $b\to u\bar u q$ contributions in two-body charmed anti-charmed baryonic $\overline B$ decays.
Comments24 pages, 4 figures, 10 tables, typos and some diagrams corrected, some discussion expanded
