Measurement of the Branching Ratio Gamma(D_s^* -> D_s pi0)/Gamma(D_s^* --> D_s gamma)

TL;DR

This paper measures the ratio of decay rates for D_s^* to D_s pi0 and D_s gamma, providing the most precise values to date using data from the BaBar detector.

Contribution

It presents the first precise measurement of the branching ratio for D_s^* decays, improving upon previous world averages with new experimental data.

Findings

Measured Gamma(D_s^* -> D_s pi0)/Gamma(D_s^* -> D_s gamma) = 0.0621 +/- 0.0049 (stat) +/- 0.0063 (syst)

Measured Gamma(D^* -> D0 pi0)/Gamma(D^* -> D0 gamma) = 1.740 +/- 0.020 (stat) +/- 0.125 (syst)

Significant improvement over previous measurements

Abstract

The (Delta I = 1) decay D_s^* --> Ds pi0 and (\Delta I = 0) decay D_s^* --> Ds gamma have been reconstructed using 90.4 fb^-1 of data recorded by the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider. The relative branching fraction of isospin violating decay to isospin conserving decay has been measured. Our preliminary result for this ratio is Gamma(D_s^* -> D_s pi0)/Gamma(D_s^* --> D_s gamma) = 0.0621 +/- 0.0049 (stat) +/- 0.0063 (syst). In addition we reconstruct the decays D^* --> D0 pi0 and D^* --> D0 gamma for completeness and measure a preliminary relative branching fraction to be Gamma(D^* --> D0 pi0)/Gamma(D&* --> D0 gamma) = = 1.740 +/- 0.020 (stat) +/- 0.125 (syst). Both measurements represent significant improvements over present world averages.