Eur. Phys. J. C (2021) 81: 188
https://doi.org/10.1140/epjc/s10052-021-08978-0

Regular Article - Theoretical Physics

Mass spectrum and strong decays of tetraquark $\overline{c}\overline{s}qq$ states

¹ Center of High Energy Physics, Peking University, 100871, Beijing, China
² School of Mathematics and Physics, University of Science and Technology Beijing, 100083, Beijing, China
³ Advanced Science Research Center, Japan Atomic Energy Agency, 319-1195, Tokai, Ibaraki, Japan
⁴ Nishina Center for Accelerator-Based Science, RIKEN, 351-0198, Wako, Japan
⁵ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871, Beijing, China

^a wgj@pku.edu.cn

Received: 31 October 2020
Accepted: 13 February 2021
Published online: 25 February 2021

Abstract

We systematically study the mass spectrum and strong decays of the S-wave $\overline{c}\overline{s}qq$ states in the compact tetraquark scenario with the quark model. The key ingredients of the model are the Coulomb, the linear confinement, and the hyperfine interactions. The hyperfine potential leads to the mixing between different color configurations, and to the large mass splitting between the two ground states with $I(J^P)=0(0^{+})$ and $I(J^P)=1(0^{+})$. We calculate their strong decay amplitudes into the ${\overline{D}}^{(\ast )}{K}^{(\ast )}$ channels with the wave functions from the mass spectrum calculation and the quark-interchange method. We examine the interpretation of the recently observed $X_0(2900)$ as a tetraquark state. The mass and decay width of the $I(J^P)=1(0^{+})$ state are $M=2941$ MeV and ${\mathrm{\Gamma }}_X=26.6$ MeV, respectively, which indicates that it might be a good candidate for $X_0(2900)$. Meanwhile, we also obtain an isospin partner state $I(J^P)=0(0^{+})$ with $M=2649$ MeV and ${\mathrm{\Gamma }}_{X\to \overline{D}K}=48.1$ MeV, respectively. Future experimental search for X(2649) will be very helpful.