title: Decoding the X(5568) as a Fully Open-Flavor sub[over ¯]d[over ¯] Tetraquark State.
abstract: We investigate the recent evidence for a charged X(5568) meson as an exotic open-flavor tetraquark state sub[over ¯]d[over ¯] with J^{P}=0^{+}/1^{+} in the framework of QCD sum rules. We use the color antisymmetric [3[over ¯]_{c}]_{su}⊗[3_{c}]_{b[over ¯]d[over ¯]} tetraquark currents in both scalar and axial-vector channels to perform evaluations and numerical analyses. Our results imply that the X(5568) can be interpreted as both the scalar sub[over ¯]d[over ¯] tetraquark state and the axial-vector one, which are in good agreement with the experimental measurement. We also discuss the possible decay patterns of the X(5568) and suggest to search for its neutral partner in the radiative decay into B_{s}^{0}γ and B_{s}^{*}γ, which can be used to determine its spin-parity quantum numbers. Moreover, we predict its charmed partner state around 2.55 GeV with the quark content suc[over ¯]d[over ¯] and J^{P}=0^{+}/1^{+}.
authors.affiliation: Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China.
authors.forename: Hua-Xing
authors.initials: HX
authors.lastname: Chen
authors.affiliation: School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.|Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
authors.forename: T G
authors.initials: TG
authors.lastname: Steele
authors.affiliation: School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.|Center of High Energy Physics, Peking University, Beijing 100871, China.
authors.forename: Shi-Lin
authors.initials: SL
authors.lastname: Zhu