Dressed-quarks and the Roper resonance

TL;DR

This paper uses Dyson-Schwinger equations to analyze the light hadron spectrum, revealing that the Roper resonance is a radial excitation of the nucleon with a meson cloud, aligning with recent EBAC conclusions.

Contribution

It provides a unified Dyson-Schwinger equation framework to describe the Roper resonance as a dressed-quark core with meson cloud effects, offering new insights into its structure.

Findings

Roper is a radial excitation of the nucleon core

The spectrum matches recent EBAC conclusions

The meson cloud significantly influences the Roper's properties

Abstract

A Dyson-Schwinger equation calculation of the light hadron spectrum, which correlates the masses of meson and baryon ground- and excited-states within a single framework, produces a description of the Roper resonance that corresponds closely with conclusions drawn recently by EBAC. Namely, the Roper is a particular type of radial excitation of the nucleon's dressed-quark core augmented by a material meson cloud component. There are, in addition, some surprises.