Strong decays of the newly observed $D(2550)$, $D(2600)$, $D(2750)$, and $D(2760)$

Abstract

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 $|1{D_2}^{\prime }{>}_H$ ($J^P=2^{-}$) via the $1^1{D}_2$-$1^3{D}_2$ mixing. The $D(2600)$ favors the low-mass mixed state $|(SD{)}_1{>}_L$ $(J^P=1^{-})$ via the $1^3{D}_1$-$2^3{S}_1$ mixing. The $D(2550)$ as the $2^1{S}_0$ assignment bears controversies for its too broad width given in experiments.

Comments: 8 pages, 5 figures; The review of the model is added. Some discussion of the $D(2750)$ is included