$Z_b(10650)$ and $Z_b(10610)$ states in a chiral quark model

Abstract

We perform a systematic study of $B{\bar{B}}^{\ast }$, $B^{\ast }{\bar{B}}^{\ast }$, $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ systems by using effective interaction in our chiral quark model. Our results show that the interactions of $B{\bar{B}}^{\ast }$, $B^{\ast }{\bar{B}}^{\ast }$, $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ states are attractive, which consequently result in $B{\bar{B}}^{\ast }$, $B^{\ast }{\bar{B}}^{\ast }$, $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ bound states. The recent observed exotic-like hadrons of $Z_b(10610)$ and $Z_b(10650)$ are, therefore in our approach, interpreted as loosely bound states of $B{\bar{B}}^{\ast }$ and $B^{\ast }{\bar{B}}^{\ast }$, while X(3872) and Y(3940) are $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ molecule states, respectively.

Comments: 8 pages, 4 figures