Generating a resonance-like structure in the reaction $B_c\to B_s \pi\pi$

Understand

We investigate the process $B_c^+\to B_s^0\pi^+\pi^0$ via $B\bar{K}^*$ rescattering.

• The kinematic conditions for triangle singularities are perfectly satisfied in the rescattering diagrams.
• A resonance-like structure around the $B\bar{K}$ threshold, which we denote as $X(5777)$, is predicted to be present in the invariant mass distribution of $B_s^0 \pi^+$.
• Because the relative weak $B\bar{K}$ $(I=1)$ interaction does not support the existence of a dynamically generated hadronic molecule, the $X(5777)$ can be identified as a pure kinematical effect due to the triangle singularity.