Semileptonic $\Lambda_b \to \bar \nu_l l \Lambda_c(2595)$ and $\Lambda_b \to \bar \nu_l l \Lambda_c(2625)$ decays in the molecular picture of $\Lambda_c(2595)$ and $\Lambda_c(2625)$

Abstract

We evaluate the partial decay widths for the semileptonic $\Lambda_b \to \bar \nu_l l \Lambda_c(2595)$ and $\Lambda_b \to \bar \nu_l l \Lambda_c(2625)$ decays from the perspective that these two $\Lambda^*_c$ resonances are dynamically generated from the $DN$ and $D^*N$ interaction with coupled channels. We find that the ratio of the rates obtained for these two reactions is compatible with present experimental data and is very sensitive to the $D^* N$ coupling, which becomes essential to obtain agreement with experiment. Together with the results obtained for the $\Lambda_b \to \pi^- \Lambda^*_c$ reactions, it gives strong support to the molecular picture of the two $\Lambda^*_c$ resonances and the important role of the $D^*N$ component neglected in prior studies of the $\Lambda_c(2595)$ from the molecular perspective.