The full version of the QCD light-cone sum rule method is applied to tetraquarks containing a single heavy $b$ or $c$ quark. To this end, investigations of the strong vertices $X_b{X}_b\rho$ and $X_c{X}_c\rho$ are performed, where $X_b=[su][\overline{b}\overline{d}]$ and $X_c=[su][\overline{c}\overline{d}]$ are the exotic states built of four quarks of different flavors. The strong coupling constants $G_{X_b{X}_b\rho }$ and $G_{X_c{X}_c\rho }$ corresponding to these vertices are found using the $\rho$-meson leading- and higher-twist distribution amplitudes. In the calculations, $X_b$ and $X_c$ are treated as scalar bound states of a diquark and antidiquark.

• Received 9 May 2016

DOI:https://doi.org/10.1103/PhysRevD.93.114036