Systematical investigation on the stability of doubly heavy tetraquark states

We systematically investigate the stability of the doubly heavy tetraquark states [Q1Q2][q over bar 3q over bar 4](Q=c and b, q=u, d and s) within the framework of the alternative color flux-tube model involving a multi-body confinement potential, sigma-exchange, one-gluon exchange and one-Goldstone-boson-exchange interactions. Our numerical analysis indicates that the states [bb][u over bar d over bar with 01+ and [bb][u over bar s over bar ] with 1+ are the most promising stable states against the strong interaction. The states [cc][u over bar d over bar ] with 01+, [bc][u over bar d over bar ] with 00+ and 01+, and [bb][u over bar d over bar ] with 01- as stable states are also predicted in the model. The dynamical mechanism producing those stable states with tetrahedral structure are discussed in the model. The states [bb][u over bar d over bar ] and [bc][u over bar d over bar ] with IJP=12+ would not be stable although they are, respectively, below the B over bar *B over bar * and D*B over bar * thresholds because they can decay into D-wave B over bar B over bar and DB over bar through the strong interaction. The states should have narrow widths if they really exist as our model prediction.