Origin and compositeness of baryons in chiral dynamics

The structure of baryon resonances is discussed in the dynamical approach with chiral symmetry. Defining the compositeness of a bound state through the field renormalization constant in Yukawa theory, we show that the bound state generated by an energy‐independent interaction is a purely composite particle, while the energy dependence of the chiral interaction induces some elementary component through the renormalization procedure. The quantitative measure of the compositeness clarifies the molecule structure of the bound state in the natural renormalization scheme, introduced by the constraint on the loop function.