Observation of a new charmed-strange meson

This paper reports that using the ARGUS detector at the DORIS II e+e- storage ring at DESY, the authors have obtained evidence for a new charmed-strange meson which decays into D*+K0 and its charge conjugate. Its mass is observed to be 2535.9 ± 0.6 ± 2.0 MeV/c2 and its width to be less than 4.6 MeV/c2 at the 90% confidence level. The fragmentation function is found to be hard, as expected for a state containing a leading charmed quark produced by continuum e+e- annihilation. No structure is observed at this mass in the D+K0 invariant mass spectrum, which suggests that an unnatural spin-parity is preferred