The Roper Resonance: Still Controversial 60 Years Later

TL;DR

This paper reviews the ongoing debate about the Roper resonance, utilizing lattice QCD and effective field theory to clarify its nature and distinguish between quark model states and dynamically generated states.

Contribution

It provides a comprehensive re-examination of the Roper resonance using modern theoretical tools, offering new insights into its fundamental nature.

Findings

Lattice QCD offers new perspectives on the Roper resonance.

Effective field theory helps differentiate between quark model and dynamically generated states.

The controversy about the Roper resonance persists despite recent advances.

Abstract

Few baryon resonances have generated as much discussion, even controversy, as the first positive parity excited state with nucleon quantum numbers. We re-examine the issue using insight gained from lattice QCD, complemented by Hamiltonian effective field theory. In doing so, we also examine the distinction between a state that can be naturally described as a quark model state and one that is dynamically generated.