In the $B^+\to D^+ D^-K^+$ decay, LHCb has reported the observation of the open-charm exotic states $X_{ 0,1}^0\equiv X_{ 0,1}(2900)^0$ with four different quark flavors~$(ud\bar s \bar c)$, where the subscripts (0,1) denote the spins. To confirm the discovery, we propose $\Lambda_b\to \Sigma_c^{ 0(++)} X_{ 0,1}^{ \prime\,0(--)}$ in the final state interaction, where $X_{ 0,1}^{ \prime\,0(--)}$ with $s u\bar d \bar c$ ($ds\bar u \bar c$) are the new $X_{ 0,1}$-like exotic states. More specifically, $\Lambda_c^+D_s^-$ in $\Lambda_b\to \Lambda_c^+D_s^-$ are transformed as $\Sigma_c^{ 0(++)} X_{ 0,1}^{ \prime\,0(--)}$, by exchanging $\pi^{ +(-)}$. As the order of magnitude estimates, we calculate ${ \cal B}(\Lambda_b\to \Sigma_c^{ 0(++)} X_{ 0,1}^{ \prime\,0(--)}) =(2.3\pm 0.6,4.3\pm 0.8^{ +3.3}_{ -2.5})\times 10^{ -4}$. In addition, we estimate other $b$-baryon decays with the $X_{ 0,1}$-like states, such as ${ \cal B}(\Xi_{ b}^{ 0(-)}\to \Xi_{ c}^{ 0(+)}(2645)X_{ 0}^{ \prime\,0(--)}, \Lambda_{ b}\to \Xi_{ c}^{ \prime\,0}X_{ 0,1}^{ 0})\sim 10^{ -5}$. While one needs $\Lambda_b\to \Sigma_c^{ 0(++)}M_c M$ to observe $X_{ 0,1}^{ \prime\,0(--)}\to M_c M$ with $M_c M=D_s^-\pi^+$, $\bar D^0 \bar K^0$ $(D_s^-\pi^-$, $D^-K^-)$, ${ \cal B}(\Lambda_b\to \Sigma_c^{ 0(++)} X_{ 0,1}^{ \prime\,0(--)}, X_{ 0,1}^{ \prime\,0(--)}\to M_c M)\sim 10^{ -4}$ are accessible to the LHCb experiment.
Categories: hep-ph hep-ex