# Open charm-bottom axial-vector tetraquarks and their properties

## TL;DR

This paper investigates open charm-bottom axial-vector tetraquarks using QCD sum rules, calculating their masses, couplings, and decay widths, providing predictions that are compared with existing literature.

## Contribution

It offers the first detailed QCD sum rule analysis of open charm-bottom axial-vector tetraquarks, including mass, coupling, and decay width calculations.

## Key findings

- Predicted masses of $Z_q$ and $Z_s$ tetraquarks.
- Calculated strong coupling constants for decay processes.
- Estimated decay widths for $Z_q o B_c
ho$ and $Z_s o B_c \, ext{phi}$.

## 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 \rho $ and $Z_s B_c \phi $ to determine the strong $g_{Z_qB_c \rho }$ and $g_{Z_sB_c \phi }$ couplings. For these purposes, QCD light-cone sum rule method and its soft-meson approximation are utilized. The couplings $g_{Z_qB_c \rho }$ and $ g_{Z_sB_c \phi }$, 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.