Structure of the Roper resonance from lattice QCD constraints

Abstract

Two different effective field theory descriptions of the pion-nucleon scattering data are constructed to describe the region of the Roper resonance. In one, the resonance is the result of strong rescattering between coupled meson-baryon channels, while in the other the resonance has a large bare-baryon (or quark-modellike) component. The predictions of these two scenarios are compared with the latest lattice QCD simulation results in this channel. We find that the second scenario is not consistent with lattice QCD results, whereas the first agrees with those constraints. In that preferred scenario, the mass of the quarkmodel- like state is approximately 2 GeV, with the infinite-volume Roper resonance best described as a resonance generated dynamically through strongly coupled meson-baryon channels.