Using $\Lambda_b^0(6146)$ and $\Lambda_b^0(6152)$ as probes to investigate possible $\bar{B}^{*}N$ and $D^{*}N$ molecules

Abstract

Heavy quark symmetry can help us identify the internal structure of hadrons and predict new particles. In this study, we examine the strong decay modes of the observed $\Lambda_b^0(6146)$ and $\Lambda_b^0(6152)$, assuming these two states are molecular states primarily composed of $\bar{B}^{*}N$ component. The partial decay widths of the $\bar{B}^{*}N$ molecular state into the $\pi\Sigma_b$ and $\pi\Sigma_b^{*}$ final states through hadronic loops are calculated using effective Lagrangians. Our results, when compared with LHCb observations, support the interpretation of $\Lambda_b^0(6146)$ as a molecule primarily composed of $\bar{B}^{*}N$ components. However, the decay width of $\Lambda_b^0(6152)$ cannot be accurately reproduced within the molecular state framework. Based on the above results and heavy quark symmetry, we predict the existence of $\bar{B}^{*}N$ molecular states with $J^p=5/2^{+}$, which are the heavy quark spin symmetry partners of $\Lambda_b(6146)$, with masses in the range of 6195-6200 MeV. And the main decay is $\pi\Sigma_b^{*}$ channel. Moreover, there must existence of a $D^{*}N$ molecule with $J^p=3/2^{+}$, possible corresponding to the experimentally observed $\Lambda_c(2860)^{+}$. If $\Lambda_c(2880)^{+}$ is indeed the heavy quark flavor symmetry partner of $\Lambda_b(6152)$, it would exhibit a conventional three-quark structure. Therefore, we also propose the search for a $D^{*}N$ molecule with a spin-parity of $J^p=5/2^{+}$, which would be the heavy-quark spin partner state of $\Lambda_c(2860)^{+}$. It should be noted that these baryons may be mixed states, containing both molecular and three-quark components. These results can aid experiments in exploring the internal structure of these baryons.