Understanding the internal structures of X(4140), X(4274), X(4500) and X(4700)

We investigate the newly observed X(4500) and X(4700) based on the diquark-antidiquark configuration within the framework of QCD sum rules. Both of them may be interpreted as the D-wave tetraquark states of , but with opposite color structures, which is remarkably similar to the result obtained in Chen and Zhu (Phys Rev D 83:034010, 2011) that X(4140) and X(4274) can be both interpreted as the S-wave tetraquark states of , also with opposite color structures. However, the extracted masses and these suggested assignments to these X states do depend on these running quark masses where MeV and GeV. As a byproduct, the masses of the hidden-bottom partner states of X(4500) and X(4700) are extracted to be both around 10.64 GeV, which can be searched for in the invariant mass distribution.