X(3872) revisited: the roles of OPEP and the quark degrees of freedom

The $X(3872)$ is investigated by employing the quark-hadron hybrid model, that consists of the $c\bar{c}$ core, $D^{(\ast )}\bar{D}{}^{\ast }$, $J\mathrm{/}\psi \omega$, and $J\mathrm{/}\psi \rho$ two-meson states. Due to the attraction from the $c\bar{c}$-$D\bar{D}{}^{\ast }$ coupling and from the OPEP tensor coupling, a very thin peak can appear at the $D^0\bar{D}{}^{\ast 0}$ threshold. The energy of the corresponding pole of the scattering matrix is $E=(+0.06-0.14i)$ MeV, which is on the physical sheet and above the threshold, the same as the one of the poles from the LHCb data analysis.