Isospin violating decay D_s* D_s⁰ chiral perturbation theory

We systematically calculate the isospin violating decay, D-s* -> D-s pi(0), with heavy meson chiral perturbation theory up to O(p(3)) including the loop diagrams. The O(p(3)) tree-level amplitudes contain four undetermined low energy constants. We use two strategies to estimate them. Using the nonanalytic dominance approximation, we get Gamma[D-s* -> D-s pi(0)] = 8.1(-2.6)(+3.0) eV. Using the naturalness assumption, we obtain the range of the isospin violating decay width as [5.2, 11.7] eV. These two strategies give similar sizes. We find that the contribution of the O(p(3)) corrections might be significant.