Inclusive Semileptonic Decays of the D_{s} Meson: Lattice QCD Confronts Experiments

We present the results of a first-principles theoretical study of the inclusive semileptonic decays of the D_{s} meson. We performed a state-of-the-art lattice QCD calculation by taking into account all sources of systematic errors. A detailed discussion of our lattice calculation, demonstrating that inclusive semileptonic decays can nowadays be studied on the lattice at a phenomenologically relevant level of accuracy, is the subject of a companion paper [A. De Santis et al., Inclusive semileptonic decays of the D_{s} meson: A first-principles lattice QCD calculation, Phys. Rev. D 112, 054503 (2025)PRVDAQ2470-0010]. Here, we focus on the phenomenological implications of our results. Using the current best estimates of the relevant Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, our theoretical predictions for the decay rate and for the first two lepton-energy moments are in very good agreement with the corresponding experimental measurements. We also argue that, while the inclusive D_{s} channel is not yet competitive with the exclusive channels in the |V_{cs}| determination, the situation can be significantly improved in the near future.