Di-$J\mathrm{/}\psi$ structures from the quark Pauli-blocking effect

The double-charmonium scattering states such as $J\mathrm{/}\psi J\mathrm{/}\psi$, ${\eta }_{c}J\mathrm{/}\psi$, and ${\eta }_c{\eta }_c$ are investigated by a simplified quark cluster model. It is found that the quark Pauli-principle over the $c\bar{c}c\bar{c}$ system causes a rapid increase and a node in the two-meson phase shifts. The increase is not large enough to be regarded as a resonance, but if it is seen experimentally, that is most likely the quark Pauli-blocking effect.