Search for a $D bar{D}$ bound state in the $Lambda_b rightarrow Lambda Dbar{D}$ process

We have investigated the process of $Lambda_bto Lambda Dbar{D}$, by taking into account the contributions from the $s$-wave $Dbar{D}$ interaction within the coupled-channel unitary approach, and the intermediate $psi(3770)$ resonance. In addition to the peak of the $psi(3770)$, an enhancement near the $Dbar{D}$ mass threshold is found in the $Dbar{D}$ invariant mass distributions, which should be the reflection of the $Dbar{D}$ bound state. We would like to encourage our experimental colleagues to measure the $Dbar{D}$ invariant mass distribution of the $Lambda_bto Lambda Dbar{D}$ process, which is crucial to search for the $Dbar{D}$ bound state and to understand the heavy-hadron heavy-hadron interactions.