We use the interacting instanton liquid model (IILM) as a tool to study the role played by the chiral interactions in the lowest-lying vector and axial-vector meson resonances. We find that narrow $a_1$ and $\rho$ meson resonances can be generated by instanton-induced chiral forces, even in the absence of confinement. In the IILM, these hadrons are found to have masses only about 30% larger than the experimental value and small width $\lesssim 10–50\mathrm{MeV}$. This result suggests that chiral interactions are very important in these systems and provide most of their mass. We explore the decaying patterns of the $\rho$ meson, in the absence of confinement. We argue that, in our model where only chiral forces are switched on, this meson decays dissociating into its quark-antiquark constituents.

• Received 2 February 2007

DOI:https://doi.org/10.1103/PhysRevD.75.054024