A Theory of X and Z Multiquark Resonances

TL;DR

This paper proposes a diquark-antidiquark potential barrier model for tetraquark resonances, explaining various experimental observations and predicting isospin multiplets, thus advancing the theoretical understanding of exotic hadrons.

Contribution

It introduces a novel potential barrier hypothesis for diquark-antidiquark interactions in tetraquarks, addressing longstanding questions and making specific predictions about resonance properties.

Findings

Compatible with current limits on charged X states

Explains suppression of quarkonium decay channels

Predicts isospin triplets and singlets for Z particles

Abstract

We introduce the hypothesis that diquarks and antidiquarks in tetraquarks are separated by a potential barrier. We show that this notion can answer satisfactorily long standing questions challenging the diquark-antidiquark model of exotic resonances. The tetraquark description of X and Z resonances is shown to be compatible with present limits on the non-observation of charged partners X^+-, of the X(3872) and the absence of a hyperfine splitting between two different neutral states. In the same picture, Z_c and Z_b particles are expected to form complete isospin triplets plus singlets. It is also explained why the decay rate into final states including quarkonia are suppressed with respect to those having open charm/beauty states.