Precision measurement of theDs*+-Ds+mass difference

We have measured the vector-pseudoscalar mass splitting M(${\mathit{D}}_{\mathit{s}}^{\mathrm{*}+}$)-M(${\mathit{D}}_{\mathit{s}}^{+}$)=144.22±0.47±0.37 MeV significantly more precisely than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference M(${\mathit{D}}^{\mathrm{*}0}$)-M(${\mathit{D}}^0$) using the radiative decay ${\mathit{D}}^{\mathrm{*}0}$→${\mathit{D}}^0$γ, obtaining [M(${\mathit{D}}_{\mathit{s}}^{\mathrm{*}+}$)-M(${\mathit{D}}_{\mathit{s}}^{+}$)]-[M(${\mathit{D}}^{\mathrm{*}0}$)-M(${\mathit{D}}^0$)] =2.09±0.47±0.37 MeV. This is then combined with our previous high-precision measurement of M(${\mathit{D}}^{\mathrm{*}0}$)-M(${\mathit{D}}^0$), which used the decay ${\mathit{D}}^{\mathrm{*}0}$→${\mathit{D}}^0$ ${\mathrm{\pi }}^0$. We also measure the mass difference M(${\mathit{D}}_{\mathit{s}}^{+}$)-M(${\mathit{D}}^{+}$)=99.5±0.6±0.3 MeV, using the φ${\mathrm{\pi }}^{+}$ decay modes of the ${\mathit{D}}_{\mathit{s}}^{+}$ and ${\mathit{D}}^{+}$ mesons.