Quark models: What can they teach us?

TL;DR

This paper reviews the historical and current role of quark models in hadronic physics, emphasizing a chiral quark model's ability to explain phenomena like chiral symmetry breaking and restoration.

Contribution

It introduces a chiral quark model based on quantum field theory that effectively studies chiral symmetry phenomena in QCD and hadron spectra.

Findings

Chiral quark model explains spontaneous chiral symmetry breaking.

Model provides insights into chiral restoration at finite temperatures.

Supports classification and understanding of hadrons beyond simple quark states.

Abstract

Quark models have a more than 60-year history and through this time they served as a powerful investigation and prediction tool in hadronic physics. In recent years, a lot of new experimental information has been arriving on hadrons that do not qualify as simple quark model states. Yet, quark models remain the cornerstone of the classification scheme for hadrons, provide valuable insights into various phenomena inherent in QCD, and facilitate gaining a clear and physically transparent picture of the underlying physics. In the spotlight of this review is a chiral quark model inspired by quantum field theory approach to confined quarks. The model is well suited for studies of spontaneous breaking of chiral symmetry in the vacuum of QCD as well as its implications in the spectrum of hadrons. It can also be employed to investigate chiral restoration at finite temperatures.