The strong decay properties of the newly observed $D(2550)$, $D(2600)$, $D(2750)$, and $D(2760)$ are studied in a constituent quark model. It is predicted that the $D(2760)$ and $D(2750)$ seem to be two overlapping resonances. The $D(2760)$ could be identified as the $1{}^{3}D_3$ with $J^P=3^{-}$, while the $D(2750)$ is most likely to be the high-mass mixed state $|1D_2{}^{\prime }{⟩}_H$ ($J^P=2^{-}$) via the $1{}^{1}D_2\mathrm{\text{−}}1{}^{3}D_2$ mixing. The $D(2600)$ favors the low-mass mixed state $|(SD{)}_1{⟩}_L$ ($J^P=1^{-}$) via the $1{}^{3}D_1\mathrm{\text{−}}2{}^{3}S_1$ mixing. The $D(2550)$ as the $2{}^{1}S_0$ assignment bears controversies for its too-broad width given in experiments.

• Received 3 September 2010

DOI:https://doi.org/10.1103/PhysRevD.82.114014