<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>2590</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> as a dominant <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>c</mml:mi><mml:mover accent="true"><mml:mi>s</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> state with a small <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msup><mml:mi>K</mml:mi></mml:mrow></mml:math> component
Jia-Ming Xie, Ming-Zhu Liu, Li‐Sheng Geng
Abstract
The recently discovered ${D}_{s0}(2590)$ state by the LHCb collaboration was regarded as the first excited state of $^{1}{S}_{0}$ 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 $c\overline{s}$ state, and show that the coupled-channel interaction induces an 88 MeV shift with respect to the conventional quark model $c\overline{s}$ 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 ${D}_{s0}(2590)$.