Description of the newly observed ${\Xi }_c^0$ states as molecular states

Abstract

Very recently, three new structures ${\Xi }_c(2923{)}^0$, $\Xi (2938{)}^0$, and $\Xi (2964{)}^0$ at the invariant mass spectrum of ${\Lambda }_c^{+}{K}^{-}$ observed by the LHCb Collaboration triggers a hot discussion about their inner structure. In this work, we study the strong decay mode of the newly observed ${\Xi }_c$ assuming that the ${\Xi }_c$ is a $\bar{D}\Lambda -\bar{D}\Sigma$ molecular state. With the possible quantum numbers $J^p=1/2^{\pm }$ and $3/2^{\pm }$, the partial decay widths of the $\bar{D}\Lambda -\bar{D}\Sigma$ molecular state into the ${\Lambda }_c^{+}{K}^{-}$, ${\Sigma }_c^{+}{K}^{-}$,and ${\Xi }_c^{+}{\pi }^{-}$ final states through hadronic loop are calculated with the help of the effective Lagrangians. By comparison with the LHCb observation, the current results of total decay width support the $\Xi (2923{)}^0$ as $\bar{D}\Lambda -\bar{D}\Sigma$ molecule while the decay width of the ${\Xi }_c(2938{)}^0$ and $\Xi (2964{)}^0$ can not be well reproduced in the molecular state picture. In addition, the calculated partial decay widths with $S$ wave $\bar{D}\Lambda -\bar{D}\Sigma$ molecular state picture indicate that allowed decay modes, ${\Xi }_c^{+}{\pi }^{-}$, may have the biggest branching ratios for the ${\Xi }_c(2923)$. The experimental measurements for this strong decay process could be a crucial test for the molecule interpretation of the ${\Xi }_c(2923)$.

Comments: arXiv admin note: text overlap with arXiv:1002.0218 by other authors