Doubly heavy tetraquarks including one-pion exchange potential

Spectrum of the doubly heavy tetraquarks is studied in a constituent quark model including one-pion exchange (OPE) potential. Central and tensor forces induced by OPE between two light quarks are considered. Our results show that $I(J^P)=0(1^+)$ compact bound states are shifted up because of the repulsive central force between $\bar{q}\bar{q}$. This effect possibly leads to the small binding energy in $T_{cc}$. In addition, a $I(J^P)=1(1^+)$ resonant state is reported with $ E=10641 \ \rm{MeV},\Gamma=15 \ \rm{MeV}$ and $ E=10640 \ \rm{MeV},\Gamma=15 \ \rm{MeV}$, without and with including OPE potential, respectively. The repulsive central force and attractive tensor force almost cancel with each other and leave a small energy difference when OPE potential is included.