Hadron resonances with coexistence of different natures
  We discuss coexistence/mixing of different natures of hadronic composite (molecule) and elementary (quark-intrinsic) ones in hadron resonances. The discussions here are based on our previous publications on the origin of hadron resonances \cite{Hyodo:2008xr}, exotic $\bar D$ meson-nucleons as hadronic composites containing one anti-heavy quark \cite{Yamaguchi:2011xb}, and the study of $a_1$ as a typical example to show explicitly the mixing of the two different natures \cite{Nagahiro:2011jn}. In all cases, interactions are derived from the chiral dynamics of the light flavor sector. These interactions generate in various cases hadronic composite/molecule states, serving varieties of structure beyond the conventional quark model. 
Atsushi Hosaka, Tetsuo Hyodo, Daisuke Jido, Hideko Nagahiro, Kanabu   Nawa, Shunsuke Ohkoda, Sho Ozaki, Yasuhiro Yamaguchi, ...
hep-ph