Ds0(2590) as a dominant c(s)over-bar state with a small D*K component

The recently discovered D-s0 (2590) state by the LHCb collaboration was regarded as the first excited state of S-1(0) charmed-strange meson. Its mass is, however, lower than the Godfrey-Isgur quark model prediction by about 80 MeV. In this work, we take into account the D*K contribution to the bare c (s) over bar state, and show that the coupled-channel interaction induces an 88 MeV shift with respect to the conventional quark model c (s) over bar state, which is much closer to the experimental mass. Our study shows that in addition to 5-wave, P-wave coupled-channel interactions also play a role for hadrons located close to two-hadron thresholds. We further scrutinize the unquenched quark model results with a model independent approach. It is shown that the two-body D*K decay width is proportional to the weight of the D*K component. To saturate the experimental total decay width with the D*K partial decay width we need a weight of about 60% while to reproduce the unquenched quark model result a weight of about 5% is needed. Therefore, we encourage future experimental studies on the two-body D*K partial decay of D-s0(2590).

Automated summary

The study reveals that the experimental mass of the D-s0 (2590) state differs from the prediction of the traditional quark model due to coupled-channel interactions. Additionally, the two-body D*K decay width is proportional to the weight of the D*K component, providing important insights into the properties of the D-s0 (2590) state.