$\rho \to \pi \pi$ Hadronic Decay in the Nambu-Jona-Lasinio Model: Mass-Width Interplay and Beyond-RPA Corrections

Qing-Wu Wang, Xiao-Fu Ł\textü, Hua-Zhong Guo

We present a novel framework for analyzing unstable composite particles using Green's functions and dispersion relations. As an illustrative example, we explore the $\rho$ vector meso…