Triangle relations for XY Z states

We propose novel triangle relations, not the well-known triangle singularity, for better understanding of the exotic XY Z states. Nine XY Z resonances, X(3872), Y (4230), Z(c)(3900), X(4012), Y (4360/4390), Z(c)(4020), X(4274), Y (4660), and Z(cs)(3985) have been classified into triples to construct three triangles based on the assumption that they are all tetra-quark states. Here X(4012) has not been observed experimentally yet, and we predict its mass and roughly the width. 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 XY Z states will benefit from our results.

Automated summary

The study proposes novel triangle relations to understand exotic XYZ states, classifying nine XYZ resonances into triples and making new predictions and suggestions for experimental channel exploration.