https://doi.org/10.1140/epjc/s10052-017-4737-5
Regular Article - Theoretical Physics
Understanding the internal structures of X(4140), X(4274), X(4500) and X(4700)
1
School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing, 100191, China
2
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
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
* e-mail: wec053@mail.usask.ca
Received:
11
January
2017
Accepted:
3
March
2017
Published online:
15
March
2017
We investigate the newly observed X(4500) and X(4700) based on the diquark–antidiquark configuration within the framework of QCD sum rules. Both of them may be interpreted as the D-wave 
tetraquark states of 
, but with opposite color structures, which is remarkably similar to the result obtained in Chen and Zhu (Phys Rev D 83:034010, 2011) that X(4140) and X(4274) can be both interpreted as the S-wave tetraquark states of 
, also with opposite color structures. However, the extracted masses and these suggested assignments to these X states do depend on these running quark masses where 
MeV and 
GeV. As a byproduct, the masses of the hidden-bottom partner states of X(4500) and X(4700) are extracted to be both around 10.64 GeV, which can be searched for in the 
invariant mass distribution.
© The Author(s), 2017
