Towards a theory of hadron resonances

In this review, we present the current state of the art of our understanding of the spectrum of excited strongly interacting particles and discuss methods that allow for a systematic and model-independent calculation of the hadron spectrum. These are lattice QCD and effective field theories. Synergies between both approaches can be exploited allowing for a deeper understanding of the hadron spectrum. Results based on effective field theories and hadron-hadron scattering in lattice QCD or combinations thereof are presented and discussed. We also show that the often used Breit-Wigner parametrization is at odds with chiral symmetry and should not be used in case of strongly coupled channels.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this review, the current understanding of the excited strongly interacting particle spectrum is presented. The systematic and model-independent calculation methods, namely lattice QCD and effective field theories, are discussed. The synergies between these approaches can provide a deeper understanding of the hadron spectrum. The use of the Breit-Wigner parametrization is shown to be inconsistent with chiral symmetry and should be avoided in strongly coupled channels.