The impact of quark many-body effects on exotic hadrons

We investigate the exotic hadrons consisting of two light quarks and two heavy antiquarks, $(q\bar{Q})$-$(q\bar{Q})$. The spin-dependent term between quarks is known to give an attraction to the $ud$ spin-0 component in the isospin-0 $u\bar{c}d\bar{c}$ system, $T_{cc}$. 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 $T_{cc}$, which is preferred from the experiment, and a deep bound state for $T_{bb}$.