Branching fractions and direct CP asymmetries of charmless decay modes at the Tevatron

Abstract

We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for $B^{0}$ and $B^{0}_{s}$ decay modes into pairs of charmless charged hadrons (pion or kaon). The data set for this update amounts to 1 fb$^{-1}$ of $\bar{p}p$ collisions at $\sqrt{s}=1.96 \rm{TeV}$. We report the first observation of the $B^{0}_{s} \to K^{-}\pi^{+}$ mode and a measurement of its branching fraction and direct CP asymmetry. We also observe for the first time two charmless decays of $b$-baryon: $\Lambda^{0}_{b} \to p\pi^{-}$ and $\Lambda^{0}_{b} \to pK^{-}$.