Tetraquarks in the 1/N Expansion: a New Appraisal

TL;DR

This paper analyzes the conditions for tetraquark states to appear in the 1/N expansion of QCD, proposing a minimal non-planar solution that predicts narrow tetraquark states and their possible mixing with quarkonia.

Contribution

It introduces a new non-planar solution for tetraquarks in the 1/N expansion, identifying minimal topologies and implications for experimental detection.

Findings

Tetraquark poles can appear at a specific order in 1/N expansion.

A minimal non-planar topology supports narrow tetraquark states.

Mixing allows P-wave tetraquarks to couple to e^+e^- processes.

Abstract

We discuss the necessary, albeit not sufficient, conditions for tetraquark poles to occur in the 1/N expansion of QCD and find the minimum order at which such poles may appear. Assuming tetraquark poles, we find a new non-planar solution with the minimal number of topologies and tetraquark species. The solution implies narrow states. Mixing with quarkonium states is allowed so that P-wave tetraquarks with J^PC=1^-- would couple to e^+e^-.