Decoding the X(5568) as a Fully Open-Flavor sub[over ¯]d[over ¯] Tetraquark State

Wei Chen; Hua-Xing Chen; Xiang Liu; T G Steele; Shi-Lin Zhu

doi:10.1103/PhysRevLett.117.022002

Decoding the X(5568) as a Fully Open-Flavor sub[over ¯]d[over ¯] Tetraquark State

Phys Rev Lett. 2016 Jul 8;117(2):022002. doi: 10.1103/PhysRevLett.117.022002. Epub 2016 Jul 6.

Authors

Wei Chen¹, Hua-Xing Chen², Xiang Liu^{3

4}, T G Steele¹, Shi-Lin Zhu^{5

6

7}

Affiliations

¹ Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
² School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China.
³ School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
⁴ Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000, China.
⁵ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
⁶ Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
⁷ Center of High Energy Physics, Peking University, Beijing 100871, China.

PMID: 27447501
DOI: 10.1103/PhysRevLett.117.022002

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^{+}.