Resonance $X(5568)$ as an exotic axial-vector state

TL;DR

This paper models the exotic resonance $X(5568)$ as a diquark-antidiquark state and calculates its mass, coupling, and decay width using QCD sum rules, comparing results with experimental data and other theories.

Contribution

It provides a novel QCD sum rule analysis of the $X(5568)$ as an axial-vector tetraquark, including decay width predictions and comparison with experimental findings.

Findings

Predicted mass and coupling constants consistent with experimental data.

Calculated decay width of $X(5568) o B_s^{ ext{*}}\pi$.

Supported the tetraquark interpretation of $X(5568)$.

Abstract

The mass and meson-current coupling constant of the resonance $X(5568)$, as well as the width of the decay $X(5568)\to B_s^{\ast}\pi$ are calculated by modeling the exotic $X(5568)$ resonance as a diquark-antidiquark state $% X_b=[su][bd]$ with quantum numbers $J^{P}=1^{+}$. The calculations are made employing QCD two-point sum rule method, where the quark, gluon and mixed vacuum condensates up to dimension eight are taken into account. The sum rule approach on the light-cone in its soft-meson approximation is used to explore the vertex $X_bB_{s}^{\ast}\pi$ and extract the strong coupling $% g_{X_bB_{s}^{\ast}\pi}$, which is a necessary ingredient to find the width of the $X_b \to B_s^{\ast}\pi^{+}$ decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.