# Search for $b \to u$ transitions in $B^- \to [K^+\pi^-\pi^0]_D K^-$

Abstract : We search for decays of a B meson into a neutral D meson and a kaon, with the D meson decaying into K+pi-pi0. This final state can be reached through the b --> c transition B- -> D0K- followed by the doubly Cabibbo-suppressed D0 --> K+pi-pi0, or the b --> u transition B- --> D0bar K- followed by the Cabibbo-favored D0bar --> K+ pi-pi 0. The interference of these two amplitudes is sensitive to the angle gamma of the unitarity triangle. We present preliminary results based on 226 10^{6} e+e- --> Y(4s) --> BBbar events collected with the BABAR detector at SLAC. We find no significant evidence for these decays and we set a limit R_ADS =(BR(B- -->[K+pi-pi0]_D K-)+ BR(B+ --> [K-pi+pi0]_D K+))/(BR(B- -->[K-p i+pi0]_D K-)+ BR(B+ --> [K+pi-pi0]_D K+))<0.039 at 95% confidence level, which we translate with a Bayesian approach into r_B = |A(B- --> D0bar K-)|/|A(B- --> D0bar K-)| < 0.185 at 95% confidence level.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00166222
Contributor : Dominique Girod <>
Submitted on : Thursday, August 2, 2007 - 9:18:51 AM
Last modification on : Sunday, June 20, 2021 - 3:35:10 AM

### Citation

B. Aubert, M. Bona, D. Boutigny, Y. Karyotakis, J.P. Lees, et al.. Search for $b \to u$ transitions in $B^- \to [K^+\pi^-\pi^0]_D K^-$. Physical Review D, American Physical Society, 2007, 76, pp.111101. ⟨10.1103/PhysRevD.76.111101⟩. ⟨in2p3-00166222⟩

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