Measurement of the Branching Ratios Gamma(D_s*+ -> D_s+ pi0)/Gamma(D_s*+ -> D_s+ gamma) and Gamma(D0+ -> D0 pi0)/Gamma(D0* -> D0 gamma)

Abstract

Data samples corresponding to the isospin-violating decay $D_s^{\ast +}\to D_s^{+}{\pi }^0$ and the decays $D_s^{\ast +}\to D_s^{+}\gamma$, $D^{\ast 0}\to D^0{\pi }^0$ and $D^{\ast 0}\to D^0\gamma$ are reconstructed using 90.4 ${\mathrm{fb}}^{-1}$ of data recorded by the BaBar detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider. The following branching ratios are extracted: $\Gamma (D_s^{\ast +}\to D_s^{+}{\pi }^0)/\Gamma (D_s^{\ast +}\to D_s^{+}\gamma )=0.062\pm 0.005(stat.)\pm 0.006(syst.)$ and $\Gamma (D^{\ast 0}\to D^0{\pi }^0)/\Gamma (D^{\ast 0}\to D^0\gamma )=1.74\pm 0.02(stat.)\pm 0.13(syst.)$. Both measurements represent significant improvements over present world averages.

7 pages, 4 postscript figues, submitted to PRD Rapid Communications