How to understand the $\ddot{I}$ resonance from the quark model and $\ddot{I}€\ddot{I}€$ $P$-wave phase shift

Wen-Ze Zhao, Ru-Hui Ni, Jia-Jun Wu

As the lightest isovector vector meson, the $\ddot{I}$ meson is an important object for investigating the structure of resonant states in strong interactions. Owing to its strong couplin…