Tetraquarks in the 1/N Expansion: a New Appraisal

Understand

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^-.