Towards a Theoretical Understanding of the XYZ Mesons from QCD

TL;DR

This paper discusses the application of the Born-Oppenheimer approximation within QCD to understand the complex structure of XYZ mesons, which are exotic mesons containing heavy quarks and additional constituents.

Contribution

It introduces the use of the Born-Oppenheimer approximation combined with lattice QCD to analyze the properties of XYZ mesons from fundamental theory.

Findings

Framework for understanding XYZ mesons from QCD

Potential for predicting meson properties

Insight into tetraquark configurations

Abstract

The XYZ mesons are mesons that contain a heavy quark and antiquark but have properties that seem to require additional constituents. Some of them are electrically charged, so they must be tetraquark mesons whose additional constituents are a light quark and antiquark. The list of XYZ mesons has grown to about two dozen over the last decade. A promising approach to understanding these mesons within QCD is the Born-Oppenheimer approximation, which reduces the problem to the solution of the Schrodinger equation in potentials that can be calculated using lattice QCD. The Born-Oppenheimer approximation has not yet revealed the pattern of the XYZ mesons, but it provides a compelling framework for understanding them from the fundamental theory.