Heavy-quark symmetry and the electromagnetic decays of excited charmed strange mesons

Heavy-hadron chiral perturbation theory (HHchiPT) is applied to the decays of the even-parity charmed strange mesons, D-s0(2317) and D-s1(2460). Heavy-quark spin-symmetry predicts the branching fractions for the three electromagnetic decays of these states to the ground states D-s and D-s(*) in terms of a single parameter. The resulting predictions for two of the branching fractions are significantly higher than current upper limits from the CLEO experiment. Leading corrections to the branching ratios from chiral loop diagrams and spin-symmetry violating operators in the HHchiPT Lagrangian can naturally account for this discrepancy. Finally the proposal that the D-s0(2317) (D-s1(2460)) is a hadronic bound state of a D(D-*) meson and a kaon is considered. Leading order predictions for electromagnetic branching ratios in this molecular scenario are in very poor agreement with existing data.