Triangle relations for XYZ states

TL;DR

This paper introduces new triangle relations among XYZ exotic states, classifying nine resonances into triples to explore their tetra-quark nature and guide future experimental searches.

Contribution

It proposes novel triangle relations for XYZ states, providing a new framework to understand their tetra-quark structure and suggesting priority channels for experimental investigation.

Findings

Classified nine XYZ resonances into triples forming three triangles.

Predicted production and decay rates for suggested channels.

Provided guidance for future experimental searches based on tetra-quark hypothesis.

Abstract

We propose novel triangle relations, not the well-known triangle singularity, for better understanding of the exotic XYZ states. Nine XYZ resonances, X(3872), Y(4230), Zc(3900), X(4012), Y(4360/4390), Zc(4020), X(4274), Y(4660), and Zcs(3985) have been classified into triples to construct three triangles based on the assumption that they are all tetra-quark states. We also suggest some channels deserving search for with high priority based on this hypothesis, as well as predictions of a few production/decay rates of these channels. We hope further experimental studies of the XYZ states will benefit from our results.