Precision measurement of D meson mass differences

Using three- and four-body decays of D mesons produced in semileptonic b-hadron decays, precision measurements of D meson mass differences are made together with a measurement of the D0 mass. The measurements are based on a dataset corresponding to an integrated luminosity of 1.0fb−1 collected in pp collisions at 7\,TeV. Using the decay D0→K+K−K−π+, the D0 mass is measured to be $M(D^0) &=& 1864.75 \pm 0.15 \,({\rm stat}) \pm 0.11 \,({\rm syst}) \, \textrm{MeV/c^2}$. The mass differences M(D+)−M(D0)=4.76±0.12(stat)±0.07(syst)MeV/c^2 and M(D+s)−M(D+)=98.68±0.03(stat)±0.04(syst)MeV/c^2 are measured using the D0→K+K−π+π− and D+(s)→K+K−π+ modes.