Ds0 (2590) as a dominant c s ¯ state with a small D∗K component Ds0 (2590) AS A DOMINANT c s ¯ ... XIE JIA-MING, LIU MING-ZHU, and GENG LI-SHENG

The recently discovered Ds0(2590) state by the LHCb collaboration was regarded as the first excited state of S01 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 cs¯ state, and show that the coupled-channel interaction induces an 88 MeV shift with respect to the conventional quark model cs¯ state, which is much closer to the experimental mass. Our study shows that in addition to S-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 Ds0(2590).