We used an effective Lagrangian approach to investigate the production of the anticharmed pentaquark state $P_{ \bar{ c}s}^{ (*)-}$ with the minimal quark content $\bar{ c}sudd$ in the $\Lambda_b^0$ decay and its decay into the $\Lambda D^{ (\ast)-}$ and $\Sigma D^{ (\ast)-}$. In our calculation, the $P_{ \bar{ c}s}^{ (*)-}$ is considered as the molecule state of the $nD_{ s0(s1)}^{ -}$ in an $S$ wave, and its production and decay occur via triangle loops at the hadron level. The predicted branching fractions for the processes $\Lambda_b^0\to P_{ \bar{ c}s}^{ (*)-} D^+ $ are around $10^{ -4}\sim 10^{ -3}$. The partial decay widths of the $ P_{ \bar{ c}s}^{ (*)-} \to \Lambda D^{ (\ast)-}$ are between $0.1$ and $\sim 10~\mathrm{ MeV}$, whereas the decay widths of the $ P_{ \bar{ c}s}^{ (*)-} \to \Sigma D^{ (\ast)-}$ are about one order of magnitude smaller. It is found that the width ratios for the $P_{ \bar{ c}s}^{ (*)-}$ decays are nearly independent of the model parameter $\alpha$. It is hoped that these predictions could be helpful in searching for the anticharmed-strange pentaquark candidates in future LHCb experiments.
Categories: hep-ph