Combined study of the isospin-violating decay Ds*→Dsπ0 and radiative decay Ds*→Dsγ with intermediate meson loops

We carry out a combined study of the isospin-violating decay Ds*→Dsπ0 and radiative decay Ds*→Dsγ in an effective Lagrangian approach by taking into account the corrections from the one-loop transitions. By distinguishing the transition mechanisms of the long-distance interactions through the intermediate meson loops from the short-distance interactions through the η−π0 mixing at the tree level, the isospin-violating decay Ds*→Dsπ0 can be well constrained. In our approach, the higher-order corrections to the isospin-violating effects can involve the intermediate D(*) and K(*) scatterings. We find that the contributions from the destructive interference of intermediate meson loops via D(*)0(cu¯)K(*)+(us¯) and D(*)+(cd¯)K(*)0(ds¯) rescatterings are significant. Within the commonly accepted UV cutoff range, we obtain the partial decay width Γ[Ds*→Dsπ0]=9.92−0.66+0.76 eV. This approach allows us to describe the Ds* radiative decay in the same framework via the vector-meson-dominance model. We demonstrate that both the tree-level and one-loop transitions can be self-consistently determined if we adopt the experimental data for the branching ratio fraction of Ds*→Dsπ0 to Ds*→Dsγ. It then leads to a reliable estimate of the total decay width of Ds*, i.e., Γtotal(Ds*+)=170−12+13 eV. Published by the American Physical Society 2025