Mass-spectra of light-heavy tetraquarks

The mass spectra of light-heavy tetraquarks $cq\bar{c}\bar{q}$ (q= u, d) are computed in a non-relativistic diquark model with one-gluon exchange plus confining potential. In the diquark model, a $cq\bar{c}\bar{q}$ state is regarded to be made of a light-heavy diquark (qc) and an antidiquark $\bar{q}\bar{c}$ in triplet and antitriplet colour configuration respectively. The masses of charm mesons were calculated in order to fit the model parameters used to create the masses of tetraquarks and therefore enhance the model's reliability. The masses of $(cq\bar{c}\bar{q})$ tetra-quark states are determined to be in the range of 3.8 GeV - 4.7 GeV, which is consistent with the experimentally reported charmonium-like states. In particular, the $Z_{c}(3900)$, $Z_{c}(4430)$, and $\psi(4660)$ tetraquarks, which have been seen experimentally, may all be described by our model.