A measurement of γ from the decays Bd0(t)→D(*)+D(*)− and Bd0→Ds(*)+D(*)−

Recently, it was proposed to use measurements of Bd0(t)→D(*)+D(*)− and Bd0→Ds(*)+D(*)− decays to measure the CP phase γ. In this Letter, we present the extraction of γ using this method. We find that γ is favored to lie in one of the ranges [19.4°-80.6°](+0° or 180°), [120°-147°](+0° or 180°), or [160°-174°](+0° or 180°) at 68% confidence level (the (+0° or 180°) represents an additional ambiguity for each range). These constraints come principally from the vector-vector final states; the vector-pseudoscalar decays improve the results only slightly. Although, with present data, the constraints disappear for larger confidence levels, this study does demonstrate the feasibility of the method. Strong constraints on γ can be obtained with more data.