Search for b -> u transitions in B(0) -> D(0)K*(0) decays RID C-5223-2009

We present a study of the decays B(0) -> D(0)K*(0) and B(0) -> (D) over bar (0)K*(0) and K*(0) -> K(+)pi(-). The D(0) and the (D) over bar (0) mesons are reconstructed in the final states f = K(+)pi(-), K(+)pi(-)pi(0), K(+)pi(-)pi(+)pi(-), and their charge conjugates. Using a sample of 465 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC, we measure the ratio R(ADS) = [Gamma((B) over bar -> [f] (K) over bar (0)) + Gamma(B(0) -> [(f) over bar (D)K*(0))]/[Gamma((B) over bar (0) -> [(f) over bar (D)(K)over bar>*(0))] + Gamma(B(0) -> [f](D)K*(0))] for the three final states. We do not find significant evidence for a signal and set the following limits at 95% probability: R(ADS) (K pi) < 0.244, R(ADS) (K pi pi(0)) < 0.181, and R(ADs) (K pi pi pi)<0.391. From the combination of these three results, we find that the ratio r(S) between the b -> u and the b -> c amplitudes lies in the range [0.07,0.41] at 95% probability.