Measurement of Branching Fractions and Search for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">CP</mml:mi></mml:math>-Violating Charge Asymmetries in Charmless Two-Body<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">B</mml:mi></mml:math>Decays into Pions and Kaons

Abstract

We present measurements, based on a sample of approximately $23\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs, of the branching fractions and a search for $\mathrm{CP}$-violating charge asymmetries in charmless hadronic decays of $B$ mesons into two-body final states of kaons and pions. We find the branching fractions $B({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(4.1\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(16.7\ifmmode\pm\else\textpm\fi{}1.6\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{+}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{0})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({10.8}_{\ensuremath{-}1.9}^{+2.1}\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{+}\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\pi}}^{+})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({18.2}_{\ensuremath{-}3.0}^{+3.3}\ifmmode\pm\else\textpm\fi{}2.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{0}\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\pi}}^{0})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({8.2}_{\ensuremath{-}2.7}^{+3.1}\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. We also report $90%$ confidence level upper limits for $B$ meson decays to the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$, ${K}^{+}{K}^{\ensuremath{-}}$, and ${\overline{K}}^{0}{K}^{+}$ final states. In addition, charge asymmetries have been found to be consistent with zero, where the statistical precision is in the range of $\ifmmode\pm\else\textpm\fi{}0.10$ to $\ifmmode\pm\else\textpm\fi{}0.18$, depending on the decay mode.