Analysis of the Pc(4380)P_c(4380) and Pc(4450)P_c(4450) as pentaquark states in the diquark model with QCD sum rules

In this article, we construct the diquark-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^P={\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ hidden-charmed pentaquark states in details with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. In calculations, we use the formula $\mu=\sqrt{M^2_{P_c}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. The present predictions favor assigning the $P_c(4380)$ and $P_c(4450)$ to be the ${\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ pentaquark states, respectively.Comment: 18 pages, 5 figure

Strong decay of the heavy tensor mesons with QCD sum rules

In the article, we calculate the hadronic coupling constants $G_{D_2^*D\pi}$, $G_{D_{s2}^*DK}$, $G_{B_2^*B\pi}$, $G_{B_{s2}^*BK}$ with the three-point QCD sum rules, then study the two body strong decays $D_2^*(2460)\to D\pi$, $D_{s2}^*(2573)\to DK$, $B_2^*(5741)\to B\pi$, $B_{s2}^*(5840)\to BK$, and make predictions to be confronted with the experimental data in the future.Comment: 12 pages, 2 figure

Lowest vector tetraquark states: Y(4260/4220)Y(4260/4220) or Zc(4100)Z_c(4100)

In this article, we take the $Y(4260/4220)$ as the vector tetraquark state with $J^{PC}=1^{--}$, and construct the $C\gamma_5\otimes\stackrel{\leftrightarrow}{\partial}_\mu\otimes \gamma_5C$ type diquark-antidiquark current to study its mass and pole residue with the QCD sum rules in details by taking into account the vacuum condensates up to dimension 10 in a consistent way. The predicted mass $M_{Y}=4.24\pm0.10\,\rm{GeV}$ is in excellent agreement with experimental data and supports assigning the $Y(4260/4220)$ to be the $C\gamma_5\otimes\stackrel{\leftrightarrow}{\partial}_\mu\otimes \gamma_5C$ type vector tetraquark state, and disfavors assigning the $Z_c(4100)$ to be the $C\gamma_5\otimes\stackrel{\leftrightarrow}{\partial}_\mu\otimes \gamma_5C$ type vector tetraquark state. It is the first time that the QCD sum rules have reproduced the mass of the $Y(4260/4220)$ as a vector tetraquark state.Comment: 13 pages, 4 figures. arXiv admin note: text overlap with arXiv:1803.0574