Electromagnetic form factor ofD ^* →D transition in the time-like region

Abstract

The internal conversion processD ^* →De ⁺ e ⁻, andD ^* $\bar D$-pair production ine ⁺ e ⁻-collisions,e ⁺ e ⁻ →D ^* $\bar D$, which are described by the same electromagnetic form factor with time-like momentum transfer, have been analyzed. After carrying out a general analysis of the kinematical aspects of the one-photon mechanism has been performed and the predictions of the vector-dominance model for theD ^* →D transition form factor are discussed. It is shown that use of the asymptotic behaviour of the form factors ofD ^*+,0 →D ^+,0γ^* and the theoretical values of constants ofD ^*+,0 → D^+,0γ radiative decay enables one to determine part of the unknown parameters of these form factors. The coefficient of the internal conversion forD ^* →De ⁺ e ⁻ is calculated and is shown to be model independent.