Review of the QCD sum rules for exotic states

TL;DR

This paper reviews the application of QCD sum rules to exotic hadronic states like X, Y, Z, T, and P, discussing their possible classifications and future experimental tests.

Contribution

It provides a comprehensive overview of how QCD sum rules are used to analyze and predict properties of exotic states, including comparisons with other theoretical methods.

Findings

Predictions for exotic states that can be tested experimentally

Assignments of exotic states based on QCD sum rules

Discussion of alternative theoretical approaches

Abstract

We review the exotic states, such as the $X$, $Y$, $Z$, $T$ and $P$ states, and present their possible assignments based on the QCD sum rules. We present many predictions which can be confronted to the experimental data in the future to diagnose the exotic states. Furthermore, we also mention other theoretical methods.