Measurements of $A_{CP}(B^0\to K^{+}{\pi }^{-})$ and $A_{CP}(B_s\to {\pi }^{+}{K}^{-})$ at LHCb

Abstract

The LHCb experiment is designed to perform flavour physics measurements at the Large Hadron Collider. Using data collected during the 2010 run, we reconstruct a sample of $H_b\to h^{+}{h}^{\prime -}$ decays, where $H_b$ can be either a $B^0$ meson, a $B_s^0$ meson or a ${\Lambda }_b$ baryon, while $h$ and $h^{\prime }$ stand for $\pi$, $K$ or $p$. We provide preliminary values of the direct $\mathcal{C}\mathcal{P}$ asymmetries of the neutral $B^0$ and $B_s^0$ mesons $A_{CP}(B^0\to K^{+}{\pi }^{-})=-0.074\pm 0.033(stat.)\pm 0.008(syst.)$ and $A_{CP}(B_s^0\to {\pi }^{+}{K}^{-})=0.15\pm 0.19(stat.)\pm 0.02(syst.)$.