The Properties of $D_{s1}^{\ast }(2700{)}^{+}$

Abstract

The new particle $D_{s1}^{\ast }(2700{)}^{+}$ has stimulated many attentions. There are different assignments of its inherent properties. It may be a $2^3{S}_1$, $1^3{D}_1$ or the mixture of $2^3{S}_1-1^3{D}_1$ $c\bar{s}$ $1^{-}$ state. By considering its mass, decay modes, full width, production rate, and comparing with current experimental data, we point out that there is another more reasonable assignment: $D_{s1}^{\ast }(2700{)}^{+}$ could be identified as two resonances, one of which is a $2^3{S}_1$ state, another is a 1D state, and both are $c\bar{s}$ $1^{-}$ states. The two states have very close masses, which are around 2700 MeV, and both have broad decay widths. So in experiments, the overlapping of $DK$ or $D^{\ast }K$ invariant mass distribution coming from their decays is found, but the current experiments could not distinguish these two resonances and reported one particle.

Comments: 12 pages, 3 figures