3,166 research outputs found

    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

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    In this article, we construct the diquark-diquark-antiquark type interpolating currents, and study the masses and pole residues of the JP=32βˆ’J^P={\frac{3}{2}}^- and 52+{\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 ΞΌ=MPc2βˆ’(2Mc)2\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 Pc(4380)P_c(4380) and Pc(4450)P_c(4450) to be the 32βˆ’{\frac{3}{2}}^- and 52+{\frac{5}{2}}^+ pentaquark states, respectively.Comment: 18 pages, 5 figure

    The radiative decays Bcβˆ—Β±β†’BcΒ±Ξ³B_c^{*\pm} \to B_c^{\pm} \gamma with QCD sum rules

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    In this article, we calculate the Bcβˆ—β†’BcB_c^* \to B_c electromagnetic form-factor with the three-point QCD sum rules, then study the radiative decays Bcβˆ—Β±β†’BcΒ±Ξ³ B_c^{*\pm} \to B_c^{\pm} \gamma. Experimentally, we can study the radiative transitions using the decay cascades Bcβˆ—Β±β†’BcΒ±Ξ³β†’J/Οˆβ„“Β±Ξ½Λ‰β„“Ξ³β†’ΞΌ+ΞΌβˆ’β„“Β±Ξ½Λ‰β„“Ξ³B_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
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