Possible molecular states in $B^{(\ast )}{B}^{(\ast )}$ scatterings

We present that, if unitarizing the $B^{(\ast )}{B}^{(\ast )}$ scattering amplitudes in the constituent interchange model, one can find two bound state poles for $(I_{tot},S_{tot})=(0,1)$ $B{B}^{\ast }$ and $B^{\ast }{B}^{\ast }$ system, which corresponds to two $I(J^P)=0(1^{+})$ doubly bottomed molecular states. Furthermore, it is noticed that the virtual states in $(1,0)$ $BB$, $(1,1)$ $B{B}^{\ast }$, $(1,0)$ $B^{\ast }{B}^{\ast }$, and $(1,2)$ $B^{\ast }{B}^{\ast }$ systems could produce enhancements of the module squares of the scattering $T$-matrix just above the related thresholds, which might correspond to $I(J^P)=1(0^{+})$, $1(1^{+})$, and $1(2^{+})$ doubly bottomed molecular states, respectively. The calculation may be helpful for searching for the doubly bottomed molecular state in future experiments.