From Extraction of Nucleon Resonances to LQCD
The intrinsic difficulties in extracting the hadron resonances from reaction data are illustrated by using several exactly soluble ππ ππ scattering models. The finite-volume Hamiltonian method is applied to predict spectra using two meson-exchange Hamiltonians of πN πN reactions. Within a three-channel model with πN πN , πΔ πΔ and σN σN channels, we show the advantage of the finite-volume Hamiltonian method over the approach using the Lüscher formula to test Lattice QCD calculations aimed at predicting nucleon resonances. We discuss the necessary steps for using the ANL-Osaka eight-channel Hamiltonian to predict the spectra for testing the LQCD calculations for determining the excited nucleon states up to invariant mass W=2 W=2 GeV.