Possibility of $T_{c\bar{s}}(2900)$ as the resonance-like structure induced by threshold effects

Abstract: We investigate the process $B\to \bar{D}D_s \pi$ via several rescattering processes. It is shown that the triangle singularity (TS) peak around the $D^K^$ threshold generated from the $\chi_{c1}K^* D^*$ loop is relatively narrow, which may simulate the resonance-like structure $T_{c\bar{s}}(2900)$ recently observed by LHCb in the $D_s\pi$ spectrum. However, the TS peak around the $D_s^*\rho$ threshold generated from the $D^{**} D_s^* \rho$ loop is smoothed by the broad width of $\rho$, which itself can hardly describe the $T_{c\bar{s}}(2900)$ structure. A TS signal around the $DK$ threshold generated from the $\chi_{c0}K D $ loop is also predicted.