Reanalysis of the $$Y(3940)$$ Y ( 3940 ) , $$Y(4140)$$ Y ( 4140 ) , Zc(4020) Z c ( 4020 ) , Zc(4025) Z c ( 4025 ) , and Zb(10650) Z b ( 10650 ) as molecular states with QCD sum rules

In this article, we calculate the contributions of the vacuum condensates up to dimension 10 in the operator product expansion, and study the JPC\!=0⁺⁺ , 1⁺⁻ , 2⁺⁺ D^*D̄^* , Dₛ^*D̄ₛ^* , B^*B̄^* , Bₛ^*B̄ₛ^* molecular states with the QCD sum rules. In the calculations, we use the formula μ =√M²X/Y/Z-(2MQ)² to determine the energy scales of the QCD spectral densities. The numerical results favor assigning the Zc(4020) and Zc(4025) to the JPC\!=0⁺⁺ , 1⁺⁻ or 2⁺⁺ D^*D̄^* molecular states, the $$Y(4140)$$ to the JPC\!=0⁺⁺ D^*ₛDₛ^* molecular state, the Zb(10650) to the JPC\!=1⁺⁻ B^*B̄^* molecular state, and they disfavor assigning the $$Y(3940)$$ to the ( JPC\!=0⁺⁺ ) molecular state. The present predictions can be confronted with the experimental data in the future.