Inclusive Semileptonic Decays of the Ds Meson: Lattice QCD Confronts Experiments

We present the results of a first-principles theoretical study of the inclusive semileptonic decays of the Ds 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, Inclusive semileptonic decays of the Ds 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 Ds channel is not yet competitive with the exclusive channels in the |Vcs| determination, the situation can be significantly improved in the near future.