Inclusive Semileptonic Decays of the $D_s$ Meson from Lattice QCD

by Christiane Gross (Helmholtz-Institut für Strahlen- und Kernphysik)

Tuesday 21 Oct 2025, 15:00 → 17:00 Europe/Berlin

Nußallee 14-16/0.023 (HISKP) - Lecture Hall (HISKP)

We present the results of a first-principles theoretical study of the inclusive semileptonic decays of the $D_s$ Ds meson. We performed a state-of-the-art lattice QCD calculation using the gauge ensembles produced by the Extended Twisted Mass Collaboration (ETMC) with dynamical light, strange and charm quarks with physical masses and employed the so-called Hansen-Lupo-Tantalo (HLT) method to extract the decay rate and the first two lepton-energy moments from the relevant Euclidean correlators. We have carefully taken into account all sources of systematic errors, including the ones associated with the continuum and infinite-volume extrapolations and with the HLT spectral reconstruction method. 
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 $D_s$ Ds channel is not yet competitive with the exclusive channels in the $|V_{cs}|$ |Vcs| determination, the situation can be significantly improved in the near future. 

Relevant publications : Phys.Rev.Lett. 135 (2025) 12, 121901 and Phys.Rev.D 112 (2025) 5, 054503