Open charm-bottom axial-vector tetraquarks and their properties

The charged axial-vector $J^P=1^{+}$ tetraquarks $Z_{q}=[cq][\bar {b} \bar q ]$and$Z_{s}=[cs][\bar {b} \bar s]$ with the open charm-bottom contents are studied in the diquark-antidiquark model. The masses and meson-current couplings of these states are calculated by employing QCD two-point sum rule approach, where the quark, gluon and mixed condensates up to eight dimensions are taken into account. These parameters of the tetraquark states $Z_q$ and $Z_s$ are used to analyze the vertices $Z_q{B}_c\rho$ and $Z_s{B}_c\varphi$ to determine the strong $g_{Z_q{B}_c\rho }$ and $g_{Z_s{B}_c\varphi }$ couplings. For these purposes, QCD light-cone sum rule method and its soft-meson approximation are utilized. The couplings $g_{Z_q{B}_c\rho }$ and $g_{Z_s{B}_c\varphi }$, extracted from this analysis, are applied for evaluating of the strong $Z_q \to B_c \rho$and$Z_s \to B_c \phi$ decays’ widths, which are essential results of the present investigation. Our predictions for the masses of the $Z_q$ and $Z_s$ states are confronted with similar results available in the literature.