Establish a fully consistent theoretical value of the Ds+ decay constant

Establish a fully consistent theoretical value of the $D_s^+$-meson decay constant $f_{D_s^+}$ across nonperturbative theoretical approaches, including lattice QCD and QCD sum rules.

Background

The paper reviews differing theoretical predictions for fDs+f_{D_s^+} obtained using lattice QCD and several formulations of QCD sum rules. The spread among these results is attributed to differences in nonperturbative treatments and perturbative inputs. A consistent theoretical determination is needed because the uncertainty in fDs+f_{D_s^+} is the dominant theoretical limitation in extracting ∣Vcs∣|V_{cs}| from leptonic Ds+D_s^+ decays.

References

Despite these efforts, discrepancies persist among different theoretical approaches and a fully consistent value of $f_{D_s+}$ has yet to be established, motivating further refinements in theoretical calculations of $f_{D_s+}$.

— Characterize the properties of $D_s^+$-meson decay constant and leptonic decays by using QCD sum rules within background field theory framework  (2608.17483 - Chen et al., 18 Aug 2026) in Introduction