Decoupling of higher vector mesons and charmed meson production in e+e− annihilation

The striking feature that $\text{D}$¹D¹ production is greatly enhanced at energies just above threshold is explained. We argue that higher excited vector mesons successively decouple from lower spin final states which manifests itself in an explicit decoupling scheme. This can be verified on quite general grounds. A quantitative analysis of charmed meson production near threshold is given. Further evidence of the decoupling scheme coming from old data is discussed.