Investigations on the weak decays of $D\bar{B}$ molecules

Abstract

The decays of exotic states discovered experimentally always proceed via the strong and electromagnetic interactions. Recently, a tetraquark state with the quark content $bc\bar{q}\bar{q}$ was predicted by Lattice QCD simulations. It is below the mass threshold of $D\bar{B}$, which can only decay via the weak interaction. In this work, based on the decay mechanism of $T_{cc}$ as a $D{D}^{\ast }$ molecule, we propose that the decays of the $bc\bar{q}\bar{q}$ tertaquark state as a $D\bar{B}$ molecule proceed via the Cabibbo-favored weak decays of the $\bar{B}$ or $D$ meson, accompanied by the tree-level decay modes and the triangle decay modes. Our results indicate that the branching fraction of the $D\bar{B}$ molecule decaying into ${\pi }^{+}{K}^{-}{\bar{B}}^0$ is sizable, which is a good channel to observe the $D\bar{B}$ molecule in future experiments.

Comments: Version accepted for publication, Phys.Rev.D