Speaker
Description
We systematically investigate the spectrum and decay properties of charm-strange mesons using a chiral unitary approach that combines Weinberg-Tomozawa interactions with bare $c\bar{s}$ states from the constituent quark model. The S-wave interactions in the (S,I)=(1,0) sector produce a rich $D_{sJ}$ spectrum with $J^P$=$0^+$, $1^+$, $1^-$, $2^-$. In addition to the well-known $DK$ and $D^* K$ molecular states, we also predict the existence of $D_1 K$ and $D_2 K$ molecular candidates. The decays of these $D_1 K$ and $D_2 K$ states are further studied. Triangle singularities are found to produce narrow peaks in the $D_s^*\pi$ and $D_s\pi$ invariant mass spectra near the $D^* K$ and $DK$ thresholds, respectively. The isospin-violating decays of the $D_1 K$ and $D_2 K$ molecules are predicted to have sizeable partial widths, significantly enhanced by the strong couplings inherent to molecular states. This unified picture, incorporating both molecular and quark-model components, provides phenomenological signatures for identifying these exotic candidates at current experiments.
