Open charm-bottom axial-vector tetraquarks and their properties

Abstract

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 $Z_q B_c ρ$ and $Z_s B_c ϕ$ to determine the strong $g_{Z_qB_c ρ}$ and $g_{Z_sB_c ϕ}$ couplings. For these purposes, QCD light-cone sum rule method and its soft-meson approximation are utilized. The couplings $g_{Z_qB_c ρ}$ and $ g_{Z_sB_c ϕ}$, extracted from this analysis, are applied for evaluating of the strong $Z_q \to B_c ρ$ and $Z_s \to B_c ϕ$ 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.

11 Pages, 5 Figures and 3 Tables