$a_1(1420)$ resonance as a tetraquark state and its isospin partner

Hua-Xing Chen, Er-Liang Cui, Wei Chen +3

We systematically construct tetraquark currents of $I^G{J}^{PC}=1^{-}{1}^{++}$ and classify them into types $\mathbf{A}$ (antisymmetric), $\mathbf{S}$ (symmetric) and $\mathbf{M}$ (mixed…