Light Scalar Tetraquark Mesons in the QCD Sum Rule

Understand

We study the lowest-lying scalar mesons in the QCD sum rule by considering them as tetraquark states.

• We find that there are five independent currents for each state with a certain flavor structure.
• By forming linear combinations, we find that some mixed currents give reliable QCD sum rules.
• Among various tetraquark currents, we consider those which are constructed by the diquarks having anti-symmetric and symmetric flavor structures.