https://doi.org/10.1140/epjc/s10052-014-2891-6
Regular Article - Theoretical Physics
Possible assignments of the 
, 
, and 
as axial-vector molecular states
1
Department of Physics, North China Electric Power University, Baoding, 071003, People’s Republic of China
2
Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing, 100049, People’s Republic of China
* e-mail: zgwang@aliyun.com
Received:
28
January
2014
Accepted:
5
May
2014
Published online:
20
May
2014
In this article, we construct both the color singlet–singlet type and the octet–octet type currents to interpolate , , and , and we calculate the vacuum condensates up to dimension-10 in the operator product expansion. Then we study the axial-vector hidden charm and hidden bottom molecular states with the QCD sum rules, explore the energy-scale dependence of the QCD sum rules for the heavy molecular states in details, and we use the formula 
with the effective masses 
to determine the energy scales. The numerical results support assigning , , and as the color singlet–singlet type molecular states with 
, 
, , respectively, more theoretical and experimental work is still needed to distinguish the molecule and tetraquark assignments; while there are no candidates for the color octet–octet type molecular states.
© SIF and Springer-Verlag Berlin Heidelberg, 2014
