The transition form factors for semi-leptonic weak decays of J/ψ in QCD sum rules Yu-Ming Wang, Hao Zou, Zheng-Tao Wei, Xue-Qian Li and Cai-Dian Lü Eur. Phys. J. C, 54 1 (2008) 107-121 Published online: 08 January 2008 DOI: 10.1140/epjc/s10052-007-0498-x