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

TL;DR

This paper investigates how the quark Pauli-blocking effect influences double-charmonium scattering states, revealing a rapid phase shift change that could be experimentally observed as a signature of quark-level effects.

Contribution

It introduces a simplified quark cluster model to study the impact of the quark Pauli principle on double-charmonium interactions, highlighting a specific non-resonant phase shift behavior.

Findings

Quark Pauli-blocking causes a rapid increase and a node in phase shifts.

The effect is not strong enough to form a resonance.

Experimental observation of this effect is possible.

Abstract

The double-charmonium scattering states such as $J/\psi J/\psi$, $\eta_cJ/\psi$, 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.