Application of the QCD light cone sum rule to tetraquarks: the strong vertices $X_b{X}_b\rho$ and $X_c{X}_c\rho$

Abstract

The full version of 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 $X_b=[su][\bar{b}\bar{d}]$ and $X_c=[su][\bar{c}\bar{d}]$ 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.

Comments: 10 Pages, 5 Figures and 1 Table