The Impact of Quark Many-Body Effects on Exotic Hadrons

We investigate the exotic hadrons consisting of two light quarks and two heavy antiquarks, \((q\bar{Q})\) $(q\overline{Q})$ - \((q\bar{Q})\) $(q\overline{Q})$ . The spin-dependent term between quarks is known to give an attraction to the ud spin-0 component in the isospin-0 \(u\bar{c} d\bar{c}\) $u\overline{c}d\overline{c}$ system, \(T_{cc}\) $T_{\mathit{cc}}$ . However, the said component also gets a repulsion from the partial Pauli-blocking. By the dynamical calculation with a simplified quark model, we discuss that the competition of the two effects leads to a shallow bound state for \(T_{cc}\) $T_{\mathit{cc}}$ , which is preferred from the experiment, and a deep bound state for \(T_{bb}\) $T_{\mathit{bb}}$ .