Analysis of the axial vector Bc-like tetraquark states with the QCD sum rules
In this paper, we construct the diquark-antidiquark–type current operators to study the axial vector Bc-like tetraquark states with the QCD sum rules. In the calculations, we take the energy scale formula as a powerful constraint to choose the ideal energy scales of the QCD spectral densities and add detailed discussions to illustrate why we take the energy scale formula to improve the QCD sum rules for the doubly heavy tetraquark states. The predicted masses and lie between the conventional 2P and 3P Bc states with from the potential quark models, which is a typical feature of the diquark-antidiquark–type Bc-like tetraquark states.