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

The radiative decays Bc∗±→Bc±γB_c^{*\pm} \to B_c^{\pm} \gamma with QCD sum rules

In this article, we calculate the $B_c^* \to B_c$ electromagnetic form-factor with the three-point QCD sum rules, then study the radiative decays $B_c^{*\pm} \to B_c^{\pm} \gamma$. Experimentally, we can study the radiative transitions using the decay cascades $B_c^{*\pm}\to B_c^{\pm} \gamma\to J/\psi \ell^{\pm}\bar{\nu}_{\ell} \gamma\to \mu^+ \mu^- \ell^{\pm}\bar{\nu}_{\ell} \gamma$ in the future at the LHCb.Comment: 12 pages, 9 figures. arXiv admin note: text overlap with arXiv:1307.242