2010/06/22 by P. del Amo Sanchez, The BABAR Collaboration, J. P. Lees +99 · 1 citation
Chemistry · Engineering · Physics and Astronomy · #Analytical Chemistry (journal) #Branching fraction #Chemistry #Crystallography #Electron–positron annihilation #Hadron #Particle Accelerators and Free-Electron Lasers #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Unitarity #hep-ex
paper · pdf · doi:10.1103/physrevd.82.072006
published as Phys.Rev.D82:072006,2010 · 18 pages, 13 postscript figures, submitted to Phys.Rev.D
arxiv created 2010/06/22 · openalex publication_date 2010/10/11 · arxiv updated 2014/11/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We report results from an updated study of the suppressed decays B^\ensuremath-\ensuremath→DK^\ensuremath- and B^\ensuremath-\ensuremath→D*K^\ensuremath- followed by D\ensuremath→K+\ensuremathπ^\ensuremath-, where D(*) indicates a D(*)0 or a D(*)0 meson, and D*\ensuremath→D\ensuremathπ0 or D*\ensuremath→D\ensuremathγ. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity triangle angle \ensuremathγ due to interference between the b\ensuremath→c transition B^\ensuremath-\ensuremath→D(*)0K^\ensuremath- followed by the doubly Cabibbo-suppressed decay D0\ensuremath→K+\ensuremathπ^\ensuremath-, and the b\ensuremath→u transition B^\ensuremath-\ensuremath→D(*)0K^\ensuremath- followed by the Cabibbo-favored decay D0\ensuremath→K+\ensuremathπ^\ensuremath-. We also report an analysis of the decay B^\ensuremath-\ensuremath→D(*)\ensuremathπ^\ensuremath- with the D decaying into the doubly Cabibbo-suppressed mode D\ensuremath→K+\ensuremathπ^\ensuremath-. Our results are based on 467\ifmmode×\else\texttimes\fi\phantom\rule0ex0ex106 \ensuremathΥ(4S)\ensuremath→BB decays collected with the BABAR detector at SLAC. We measure the ratios R(*) of the suppressed ([K+\ensuremathπ^\ensuremath-]DK^\ensuremath-/\ensuremathπ^\ensuremath-) to favored ([K^\ensuremath-\ensuremathπ+]DK^\ensuremath-/\ensuremathπ^\ensuremath-) branching fractions as well as the CP asymmetries A(*) of those modes. We see indications of signals for the B^\ensuremath-\ensuremath→DK^\ensuremath- and B^\ensuremath-\ensuremath→D_D\ensuremathπ0*K^\ensuremath- suppressed modes, with statistical significances of 2.1 and 2.2\ensuremathσ, respectively, and we measure: RDK=(1.1\ifmmode±\else\textpm\fi0.6\ifmmode±\else\textpm\fi0.2)\ifmmode×\else\texttimes\fi10^\ensuremath-2,\phantom\rule2em0exADK=\ensuremath-0.86\ifmmode±\else\textpm\fi0.47_\ensuremath-0.16+0.12, R_(D\ensuremathπ0)K*=(1.8\ifmmode±\else\textpm\fi0.9\ifmmode±\else\textpm\fi\phantom\rule0ex0ex0.4)\ifmmode×\else\texttimes\fi10^\ensuremath-2,\phantom\rule2em0exA_(D\ensuremathπ0)K*=+0.77\ifmmode±\else\textpm\fi0.35\ifmmode±\else\textpm\fi0.12,\phantom\rule2em0exR_(D\ensuremathγ)K*=(1.3\ifmmode±\else\textpm\fi1.4\ifmmode±\else\textpm\fi0.8)\ifmmode×\else\texttimes\fi10^\ensuremath-2,A_(D\ensuremathγ)K*=+0.36\phantom\rule0ex0ex\ifmmode±\else\textpm\fi0.94_\ensuremath-0.41+0.25, where the first uncertainty is statistical and the second is systematic. We use a frequentist approach to obtain the magnitude of the ratio rB\ensuremath≡|A(B^\ensuremath-\ensuremath→D0K^\ensuremath-)/A(B^\ensuremath-\ensuremath→D0K^\ensuremath-)|=(9.5_\ensuremath-4.1+5.1)%, with rB<16.7% at 90% confidence level. In the case of B^\ensuremath-\ensuremath→D*K^\ensuremath- we find rB*\ensuremath≡|A(B^\ensuremath-\ensuremath→D*0K^\ensuremath-)/A(B^\ensuremath-\ensuremath→D*0K^\ensuremath-)|=(9.6_\ensuremath-5.1+3.5)%, with rB*<15.0% at 90% confidence level.